FN6362 Rev 0.00 Page 1 of 26
May 27, 2008
FN6362
Rev 0.00
May 27, 2008
ISL3332, ISL3333
3.3V, ±15kV ESD Protected, Two Port, Dual Protocol (RS-232/RS-485)
Transceivers
DATASHEET
The ISL3332, ISL3333 are two port interface ICs where each
port can be independently configured as a single
RS-485/422 transceiver, or as a dual (2 Tx, 2 Rx) RS-232
transceiver. With both ports set to the same mode, two
RS-485/RS-422 transceivers, or four RS-232 transceivers
are available.
If either port is in RS-232 mode, the onboard charge pump
generates RS-232 compliant 5V Tx output levels from a
single VCC supply as low as 3.15V. The transceivers are
RS-232 compliant, with the Rx inputs handling up to 25V.
In RS-485 mode, the transceivers support both the RS-485
and RS-422 differential communication standards. The
receivers feature "full failsafe" operation, so the Rx outputs
remain in a high state if the inputs are open or shorted
together. The transmitters support up to three data rates, two
of which are slew rate limited for problem free
communications. The charge pump disables when both
ports are in RS-485 mode, thereby saving power, minimizing
noise, and eliminating the charge pump capacitors.
Both RS-232 and RS-485 modes feature loopback and
shutdown functions. Loopback internally connects the Tx
outputs to the corresponding Rx input, to facilitate board
level self test implementation. The outputs remain connected
to the loads during loopback, so connection problems (e.g.,
shorted connectors or cables) can be detected. Shutdown
mode disables the Tx and Rx outputs, disables the charge
pumps, and places the IC in a low current (35µA) mode.
The ISL3333 is a QFN packaged device that includes two
additional user selectable, lower speed and edge rate
options for EMI sensitive designs, or to allow longer bus
lengths. It also features a logic supply pin (VL) that sets the
VOH level of logic outputs, and the switching points of logic
inputs, to be compatible with another supply voltage in mixed
voltage systems. The QFN also adds RS-232 mode Tx EN
pins (DEN), and active low Rx enable pins (RXEN) to
increase design flexibility. In RS-485 applications, active low
Rx enable pins allow Tx/Rx direction control, via a single
signal per port, by connecting the corresponding DE and
RXEN pins together.
For a single port version of these devices, please see the
ISL3330, ISL3331 data sheet.
Features
15kV (HBM) ESD Protected Bus Pins (RS-232 or
RS-485)
Operates From a Single 3.3V Supply
Two Independent Ports, Each User Selectable for RS-232
(2 Transceivers) or RS-485/RS-422 (1 Transceiver)
True Flow-Through Pinouts Simplify Board Layouts
Pb-free (RoHS compliant)
Full Failsafe (Open/Short) Rx in RS-485/422 Mode
Loopback Mode Facilitates Board Self Test Functions
User Selectable RS-485 Data Rates (ISL3333 Only)
- Fast Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Mbps
- Slew Rate Limited. . . . . . . . . . . . . . . . . . . . . . . 460kbps
- Slew Rate Limited. . . . . . . . . . . . . . . . . . . . . . . 115kbps
Fast RS-232 Data Rate . . . . . . . . . . . . . . . Up to 400kbps
RS-232 Tx and Rx Enable Pins (ISL3333 Only)
Small Charge Pump Caps . . . . . . . . . . . . . . . . . 4 x 0.1µF
Low Current Shutdown Mode. . . . . . . . . . . . . . . . . . .35µA
QFN Package Saves Board Space (ISL3333 Only)
Logic Supply Pin (VL) Eases Operation in Mixed Supply
Systems (ISL3333 Only)
Applications
Gaming Applications (e.g., Slot Machines)
Single Board Computers
Factory Automation
Security Networks
Industrial/Process Control Networks
Level Translators (e.g., RS-232 to RS-422)
Point of Sale Equipment
Dual Channel RS-485 Interfaces
TABLE 1. SUMMARY OF FEATURES
PART NUMBER
NO. OF
PORTS PACKAGE OPTIONS
RS-485 DATA
RATE (bps)
RS-232 DATA
RATE (kbps) VL PIN?
RS-232 Tx
ENABLE?
ACTIVE H or L
Rx ENABLE?
LOW POWER
SHUTDOWN?
ISL3332 2 28 Ld SSOP 20M 400 NO NO NONE YES
ISL3333 2 40 Ld QFN (6 x 6mm) 20M, 460k, 115k 400 YES YES L YES
ISL3332, ISL3333
FN6362 Rev 0.00 Page 2 of 26
May 27, 2008
Ordering Information
PART NUMBER
(NOTE) PART MARKING
TEMP. RANGE
(°C)
PACKAGE
(Pb-Free) PKG. DWG. #
ISL3332IAZ* 3332 IAZ -40 to +85 28 Ld SSOP M28.209
ISL3333IRZ* 3333 IRZ -40 to +85 40 Ld QFN L40.6x6
*Add “-T” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100%
matte tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations).
Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J
STD-020.
Pinouts
ISL3332 (28 LD SSOP)
TOP VIEW
ISL3333 (40 LD QFN)
TOP VIEW
C1+
C1-
V+
A1
B1
Y1
Z1
SEL1
SEL2
Z2
Y2
B2
A2
GND
C2+
VCC
RB1
RA1
DZ1/DE1
LB
DY2
DZ2/DE2
RA2
RB2
V-
C2-
DY1
ON/OFF
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
1
40
2
3
4
5
6
7
8
9
10
30
29
28
27
26
25
24
23
22
21
39 38 37 36 35 34 33 32 31
11 12 13 14 15 16 17 18 19 20
NC
NC
NC
C1-
C1+
C2+
C2-
VCC
NC
VL
RB1
RA1
DZ1/DE1
DY1
LB
DZ2/DE2
RA2
V+
A1
B1
Y1
Z1
SEL1
SEL2
Z2
Y2
B2
SPA
A2
RXEN1
GND
SPB
GND
DEN1
RXEN2
V-
DEN2
ON/OFF
RB2
DY2
ISL3332, ISL3333
FN6362 Rev 0.00 Page 3 of 26
May 27, 2008
TABLE 2. ISL3332 FUNCTION TABLE
INPUTS RECEIVER OUTPUTS DRIVER OUTPUTS CHARGE PUMPS
(NOTE 1) MODESEL1 or 2 ON/OFF DE 1 or 2 RARBYZ
0 1 N.A. ON ON ON ON ON RS-232
X 0 X High-Z High-Z High-Z High-Z OFF Shutdown
1 1 0 ON High-Z * High-Z High-Z OFF RS-485
1 1 1 ON High-Z * ON ON OFF RS-485
NOTE:
1. Charge pumps are off if SEL1 = SEL2 = 1, or if ON/OFF = 0. If ON = 1, and either port is programmed for RS-232 mode, then the charge pumps
are on.
ISL3332 Truth Tables (FOR EACH PORT)
RS-232 TRANSMITTING MODE
INPUTS OUTPUTS
SEL1 or 2 ON/OFF DYDZYZ
010011
010110
011001
011100
0 0 X X High-Z High-Z
RS-232 RECEIVING MODE
INPUTS OUTPUT
SEL1 or 2 ON/OFF ABR
ARB
010011
010110
011001
011100
0 1 Open Open 1 1
0 0 X X High-Z High-Z
RS-485 TRANSMITTING MODE
INPUTS OUTPUTS
SEL1 or 2 ON/OFF DE1 or 2 DYYZ
111010
111101
1 1 0 X High-Z High-Z
1 0 X X High-Z High-Z
RS-485 RECEIVING MODE
INPUTS OUTPUT
SEL1 or 2 ON/OFF B-A RARB *
11 -40mV 1 High-Z
11 -200mV 0 High-Z
1 1 Open or Shorted together 1 High-Z
1 0 X High-Z High-Z
* Internally pulled high through a 40k resistor.
ISL3332, ISL3333
FN6362 Rev 0.00 Page 4 of 26
May 27, 2008
TABLE 3. ISL3333 FUNCTION TABLE
INPUTS
RECEIVER
OUTPUTS
DRIVER
OUTPUTS CHARGE
PUMPS
(NOTE 2)
DRIVER
DATA
RATE
(Mbps) MODESEL1 or 2 ON/OFF SPA SPB
RXEN 1
or 2
DEN 1
or 2 DE 1 or 2 RARBYZ
0 1 X X 0 0 N.A. ON ON High-Z High-Z ON 0.46 RS-232
0 1 X X 0 1 N.A. ON ON ON ON ON 0.46 RS-232
0 1 X X 1 0 N.A. High-Z High-Z High-Z High-Z ON 0.46 RS-232
0 1 X X 1 1 N.A. High-Z High-Z ON ON ON 0.46 RS-232
X 0 X X X X X High-Z High-Z High-Z High-Z OFF N.A. Shutdown
1 1 X X 0 N.A. 0 ON High-Z * High-Z High-Z OFF N.A. RS-485
1 1 0 0 0 N.A. 1 ON High-Z * ON ON OFF 0.46 RS-485
1 1 0 1 0 N.A. 1 ON High-Z * ON ON OFF 0.115 RS-485
1 1 1 0 0 N.A. 1 ON High-Z * ON ON OFF 20 RS-485
1 1 1 1 0 N.A. 1 ON High-Z * ON ON OFF 20 RS-485
1 1 X X 1 N.A. 0 High-Z High-Z * High-Z High-Z OFF N.A. RS-485
1 1 0 0 1 N.A. 1 High-Z High-Z * ON ON OFF 0.46 RS-485
1 1 0 1 1 N.A. 1 High-Z High-Z * ON ON OFF 0.115 RS-485
1 1 1 0 1 N.A. 1 High-Z High-Z * ON ON OFF 20 RS-485
1 1 1 1 1 N.A. 1 High-Z High-Z * ON ON OFF 20 RS-485
NOTE:
2. Charge pumps are off if SEL1 = SEL2 = 1, or if ON/OFF = 0. If ON = 1, and either port is programmed for RS-232 mode, then the charge pumps
are on.
ISL3333 Truth Tables (FOR EACH PORT)
RS-232 TRANSMITTING MODE
INPUTS OUTPUTS
SEL1 or 2 ON/OFF DEN1 or 2 DYDZYZ
01 10011
01 10110
01 11001
01 11100
0 1 0 X X High-Z High-Z
0 0 X X X High-Z High-Z
RS-232 RECEIVING MODE
INPUTS OUTPUT
SEL1 or 2 ON/OFF
RXEN 1
or 2 A B RARB
0 1 00011
0 1 00110
0 1 01001
0 1 01100
0 1 0 Open Open 1 1
0 1 1 X X High-Z High-Z
0 0 X X X High-Z High-Z
RS-485 TRANSMITTING MODE
INPUTS OUTPUTS
DATA
RATE
SEL1
or 2
ON/
OFF
DE
1 or 2 SPA SPB DYYZMbps
1 1 1 0 0 0/1 1/0 0/1 0.46
1 1 1 0 1 0/1 1/0 0/1 0.115
1 1 1 1 X 0/1 1/0 0/1 20
1 1 0 X X X High-Z High-Z N.A.
1 0 X X X X High-Z High-Z N.A.
RS-485 RECEIVING MODE
INPUTS OUTPUT
SEL1
or 2 ON/OFF
RXEN 1
or 2 B-A RARB *
110 -40mV 1 High-Z
110 -200mV 0 High-Z
1 1 0 Open or Shorted
together
1 High-Z
1 1 1 X High-Z High-Z
1 0 X X High-Z High-Z
* Internally pulled high through a 40k resistor.
ISL3332, ISL3333
FN6362 Rev 0.00 Page 5 of 26
May 27, 2008
Pin Descriptions
PIN MODE FUNCTION
GND BOTH Ground connection.
LB BOTH Enables loopback mode when low. Internally pulled-high.
NC BOTH No Connection.
ON/OFF BOTH If either port is in RS-232 mode, a low on ON/OFF disables the charge pumps. In either mode, a low disables all the outputs,
and places the device in low power shutdown. Internally pulled-high. ON = 1 for normal operation.
RXEN BOTH Active low receiver output enable. The corresponding port’s Rx is enabled when RXEN is low; Rx is high impedance when
RXEN is high. Internally pulled low. (QFN only)
SEL BOTH Interface Mode Select input. High puts corresponding port in RS-485 Mode, while a low puts it in RS-232 Mode.
VCC BOTH System power supply input (3.3V).
VLBOTH Logic-Level Supply. All TTL/CMOS inputs and outputs are powered by this supply. QFN logic input pins that are externally
tied high in an application, should use the VL supply for the high voltage level. (QFN only)
DEN RS-232 Active high driver output enable. The corresponding port’s 232 mode drivers are enabled when DEN is high; drivers are
disabled when DEN is low. Internally pulled high. (QFN only).
A RS-232 Receiver input with 15kV ESD protection. A low on A forces RA high; A high on A forces RA low.
RS-485 Inverting receiver input with 15kV ESD protection.
B RS-232 Receiver input with 15kV ESD protection. A low on B forces RB high; A high on B forces RB low.
RS-485 Noninverting receiver input with 15kV ESD protection.
DYRS-232 Driver input. A low on DY forces output Y high. Similarly, a high on DY forces output Y low.
RS-485 Driver input. A low on DY forces output Y high and output Z low. Similarly, a high on DY forces output Y low and output Z high.
DZ / DE RS-232 Driver input. A low on DZ forces output Z high. Similarly, a high on DZ forces output Z low.
RS-485 Driver output enable (DE). The driver outputs, Y and Z, are enabled by bringing DE high. They are high impedance when
DE is low. Internally pulled high when port selected for RS-485 mode.
RARS-232 Receiver output.
RS-485 Receiver output: If B > A by at least -40mV, RA is high; If B < A by -200mV or more, RA is low; RA = High if A and B are
unconnected (floating) or shorted together (i.e., full fail-safe).
RBRS-232 Receiver output.
RS-485 Not used. Internally pulled-high, and unaffected by RXEN.
Y RS-232 Driver output with 15kV ESD protection.
RS-485 Inverting driver output with 15kV ESD protection.
Z RS-232 Driver output with 15kV ESD protection.
RS-485 Noninverting driver output with 15kV ESD protection.
SP RS-485 Speed control. Internally pulled-high. (QFN only)
C1+ RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed if both ports in RS-485 Mode.
C1- RS-232 External capacitor (voltage doubler) is connected to this lead. Not needed if both ports in RS-485 Mode.
C2+ RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed if both ports in RS-485 Mode.
C2- RS-232 External capacitor (voltage inverter) is connected to this lead. Not needed if both ports in RS-485 Mode.
V+ RS-232 Internally generated positive RS-232 transmitter supply (+5.5V). C3 not needed if both ports in RS-485 Mode.
V- RS-232 Internally generated negative RS-232 transmitter supply (-5.5V). C4 not needed if both ports in RS-485 Mode.
ISL3332, ISL3333
FN6362 Rev 0.00 Page 6 of 26
May 27, 2008
Typical Operating Circuits
RS-232 MODE WITHOUT LOOPBACK
RS-485 MODE WITHOUT LOOPBACK
RS-232 MODE WITH LOOPBACK
RS-485 MODE WITH LOOPBACK
26
VCC
Y1
Z1
DY1
DZ1
0.1µF
+
0.1µF
+
0.1µF
22
23
6
7
1
2
3
15
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
28
27
RA1
A1 4
5k
RB1
B1 525
5k
C1
C2
+C3
C4
GND
+3.3V +0.1F
14
SEL1 ON/OFF
820
VCC
NOTE: PINOUT FOR SSOP
24
LB 21 VCC
SAME FOR PORT 2.
R
R
D
D
DEN1
(QFN ONLY)
VCC
RXEN1
(QFN ONLY)
26
VCC
Y1
Z1
DY1
0.1µF
+
0.1µF
+
0.1µF
22
6
7
1
2
3
15
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
28
27
RA1
A1 4
RB1
B1 5
25
C1
C2
+C3
C4
LB
21
GND
+3.3V +0.1µF
14
SEL1
820
VCC
VCC
DE1
23
VCC
NOTE: PINOUT FOR SSOP
24
D
R
VCC ON/OFF
SAME FOR PORT 2.
RXEN1
(QFN ONLY)
26
VCC
Y1
Z1
DY1
DZ1
0.1µF
+
0.1µF
+
0.1µF
22
23
6
7
1
2
3
15
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
28
27
RA1
5k
RB1
25
5k
C1
C2
+C3
C4
GND
+3.3V +0.1µF
14
SEL1 ON/OFF
820 VCC
NOTE: PINOUT FOR SSOP
24
LB 21 GND
SAME FOR PORT 2.
R
R
D
D
A1 4
B1 5
LB
Rx
DEN1
(QFN ONLY)
VCC
26
VCC
Y1
Z1
DY1
0.1µF
+
0.1µF
+
0.1µF
22
6
7
1
2
3
15
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
28
27
RA1
RB1
25
C1
C2
+C3
C4
LB
21
GND
+3.3V +0.1µF
14
SEL1
820
VCC
GND
DE1
23
VCC
NOTE: PINOUT FOR SSOP
24
D
R
VCC ON/OFF
SAME FOR PORT 2.
A1 4
B1 5
LB
Rx
ISL3332, ISL3333
FN6362 Rev 0.00 Page 7 of 26
May 27, 2008
Absolute Maximum Ratings (TA = +25°C) Thermal Information
VCC to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
VL (QFN Only) . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to VCC + 0.5V
Input Voltages
All Except A,B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.5V to 7V
Input/Output Voltages
A, B (Any Mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25V to +25V
Y, Z (Any Mode, Note 3) . . . . . . . . . . . . . . . . . . . -12.5V to +12.5V
RA, RB (non-QFN Package). . . . . . . . . . . . -0.5V to (VCC + 0.5V)
RA, RB (QFN Package) . . . . . . . . . . . . . . . . -0.5V to (VL + 0.5V)
Output Short Circuit Duration
Y, Z, RA, RB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table
Thermal Resistance (Typical) JA (°C/W) JC (°C/W)
28 Ld SSOP Package (Note 5) . . . . . . 60 N/A
40 Ld QFN Package (Notes 4, 6). . . . . 31 2.5
Maximum Junction Temperature (Plastic Package) . . . . . . . +150°C
Maximum Storage Temperature Range . . . . . . . . . .-65°C to +150°C
Pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . .see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Operating Conditions
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.
NOTES:
3. One output at a time, IOUT 100mA for 10 mins.
4. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See
Tech Brief TB379.
5. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
6. For JC, the “case temp” location is the center of the exposed metal pad on the package underside.
Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 - C4 = 0.1µF, VL = VCC (for QFN only); Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA =+25°C (Note 7)
PARAMETER SYMBOL TEST CONDITIONS
TEMP
(°C)
MIN
(Note 11) TYP
MAX
(Note 11) UNITS
DC CHARACTERISTICS - RS-485 DRIVER (SEL = VCC)
Driver Differential VOUT (no load) VOD1 Full - - VCC V
Driver Differential VOUT (with load) VOD2 R = 50 (RS-422) (Figure 1) Full 2 2.3 - V
R = 27 (RS-485) (Figure 1) Full 1.5 2 5 V
VOD3 RD = 60, R = 375, VCM = -7V to 12V
(Figure 1)
Full 1.5 - 5 V
Change in Magnitude of Driver
Differential VOUT for
Complementary Output States
VOD R = 27 or 50 (Figure 1) Full - 0.01 0.2 V
Driver Common-Mode VOUT VOC R = 27 or 50 (Figure 1) Full - - 3.0 V
Change in Magnitude of Driver
Common-Mode VOUT for
Complementary Output States
VOC R = 27 or 50 (Figure 1) Full - 0.01 0.2 V
Driver Short-Circuit Current,
VOUT = High or Low
IOS -7V (VY or VZ) 12V (Note 8) Full 35 - 250 mA
Driver Three-State Output
Leakage Current (Y, Z)
IOZ Outputs Disabled,
VCC = 0V or 3.6V
VOUT = 12V Full - - 200 µA
VOUT = -7V Full -200 - - µA
DC CHARACTERISTICS - RS-232 DRIVER (SEL = GND)
Driver Output Voltage Swing VOAll TOUTS Loaded with 3k to Ground Full ±5.0 - - V
Driver Output Short-Circuit Current IOS VOUT = 0V Full -60 - 60 mA
DC CHARACTERISTICS - LOGIC PINS (i.e., DRIVER AND CONTROL INPUT PINS)
Input High Voltage VIH1 VL = VCC if QFN Full 2.2 - - V
VIH2 2.7V VL < 3.0V (QFN Only) Full 2 - - V
VIH3 2.3V VL < 2.7V (QFN Only) Full 1.6 - - V
VIH4 1.6V VL < 2.3V (QFN Only) Full 0.7*VL--V
VIH5 1.2V VL < 1.6V (QFN Only) 25 - 0.7*VL-V
ISL3332, ISL3333
FN6362 Rev 0.00 Page 8 of 26
May 27, 2008
Input Low Voltage VIL1 VL = VCC if QFN Full - - 0.8 V
VIL2 VL 2.7V (QFN Only) Full - - 0.8 V
VIL3 2.3V VL < 2.7V (QFN Only) Full - - 0.7 V
VIL4 1.6V VL < 2.3V (QFN Only) Full - - 0.35*VLV
VIL5 1.3V VL < 1.6V (QFN Only) 25 - 0.35*VL-V
VIL6 1.2V VL < 1.3V (QFN Only) 25 - 0.25*VL-V
Input Current IIN1 Pins Without Pull-ups or Pull-downs Full -2 - 2 µA
IIN2 LB, ON/OFF, DE (SP, RXEN, DEN, if QFN) Full -25 - 25 µA
DC CHARACTERISTICS - RS-485 RECEIVER INPUTS (SEL = VCC)
Receiver Differential Threshold
Voltage
VTH -7V VCM 12V, Full Failsafe Full -0.2 - -0.04 V
Receiver Input Hysteresis VTH VCM = 0V 25 - 35 - mV
Receiver Input Current (A, B) IIN VCC = 0V or 3.0 to 3.6V VIN = 12V Full - - 0.8 mA
VIN = -7V Full -0.64 - - mA
Receiver Input Resistance RIN -7V VCM 12V, VCC = 0 (Note 9) or
3.0V VCC 3.6V
Full 15 - - k
DC CHARACTERISTICS - RS-232 RECEIVER INPUTS (SEL = GND)
Receiver Input Voltage Range VIN Full -25 - 25 V
Receiver Input Threshold VIL Full - 1.1 0.8 V
VIH Full 2.4 1.6 - V
Receiver Input Hysteresis VTH 25 - 0.5 - V
Receiver Input Resistance RIN VIN = 15V, VCC Powered Up (Note 9) Full 3 5 7 k
DC CHARACTERISTICS - RECEIVER OUTPUTS (485 OR 232 MODE)
Receiver Output High Voltage VOH1 IO = -1.5mA (VL = VCC if QFN) Full VCC-0.4 - - V
VOH2 IO = -100µA, VL 1.2V (QFN Only) Full VL-0.1 - - V
VOH3 IO = -500µA, VL = 1.5V (QFN Only) Full 1.2 - - V
VOH4 IO = -150µA, VL = 1.2V (QFN Only) Full 1.0 - - V
Receiver Output Low Voltage VOL IO = 5mA Full - 0.2 0.4 V
Receiver Short-Circuit Current IOSR 0V VO VCC Full 7 - 85 mA
Receiver Three-State Output
Current
IOZR Output Disabled, 0V VO VCC (or VL for
QFN)
Full - - 10 µA
Unused Receiver (RB) Pull-Up
Resistance
ROBZ ON/OFF = VCC, SELX = VCC (RS-485 Mode) 25 - 40 - k
POWER SUPPLY CHARACTERISTICS
No-Load Supply Current, (Note 7) ICC232 SEL1 or SEL2 = GND, LB = ON/OFF = VCC Full - 3.7 7 mA
ICC485 SEL 1 & 2 = LB = DE = ON/OFF = VCC Full - 1.6 5 mA
Shutdown Supply Current ISHDN232 ON/OFF = SELX = GND, LB = VCC,
(SPX = VL, DENX = GND if QFN)
Full - 45 100 µA
ISHDN485 ON/OFF = DEX = GND, SELX
= LB = VCC, (SPX = GND,
DENX = VL if QFN)
SSOP Full - 35 80 µA
QFN Full - 60 160 µA
ESD CHARACTERISTICS
Bus Pins (A, B, Y, Z) Any Mode Human Body Model 25 - 15 - kV
All Other Pins Human Body Model 25 - 2.5 - kV
Machine Model 25 - 200 - V
Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 - C4 = 0.1µF, VL = VCC (for QFN only); Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA =+25°C (Note 7) (Continued)
PARAMETER SYMBOL TEST CONDITIONS
TEMP
(°C)
MIN
(Note 11) TYP
MAX
(Note 11) UNITS
ISL3332, ISL3333
FN6362 Rev 0.00 Page 9 of 26
May 27, 2008
RS-232 DRIVER AND RECEIVER SWITCHING CHARACTERISTICS (SEL = GND, ALL VERSIONS AND SPEEDS)
Driver Output Transition Region
Slew Rate
SR RL=3kMeasured From
3V to -3V or -3V to 3V
CL 15pF Full - 20 30 V/µs
CL 2500pF Full 4 9 - V/µs
Driver Output Transition Time tr, tfRL=3k, CL = 2500pF, 10% - 90% Full 0.22 1.2 3.1 µs
Driver Propagation Delay tDPHL RL=3kCL= 1000pF (Figure 6) Full - 1 2 µs
tDPLH Full - 1.2 2 µs
Driver Propagation Delay Skew tDSKEW tDPHL - tDPLH (Figure 6) Full - 300 450 ns
Driver Enable Time (QFN Only) tDEN CL= 1000pF 25 - 1500 - ns
Driver Disable Time (QFN Only) tDDIS RL=5kMeasured at VOUT = ±3V,
CL=30pF
25 - 500 - ns
Driver Enable Time from Shutdown tDENSD VOUT = 3.0V, CL= 1000pF 25 - 25 - µs
Driver Maximum Data Rate DRDRL=3kCL= 500pF, One Transmitter
Switching on Each Port
Full 250 400 - kbps
Receiver Propagation Delay tRPHL CL=15pF (Figure 7) Full - 40 120 ns
tRPLH Full - 58 120 ns
Receiver Propagation Delay Skew tRSKEW tRPHL - tRPLH (Figure 7) Full - 18 40 ns
Receiver Maximum Data Rate DRRCL= 15pF Full 0.46 2 - Mbps
Receiver Enable to Output Low tZL QFN Only, CL = 15pF, SW = VCC Full - 18 - ns
Receiver Enable to Output High tZH QFN Only, CL = 15pF, SW = GND Full - 18 - ns
Receiver Disable from Output Low tLZ QFN Only, CL = 15pF, SW = VCC Full - 22 - ns
Receiver Disable from Output High tHZ QFN Only, CL = 15pF, SW = GND Full - 22 - ns
Receiver Enable from Shutdown to
Output Low
tZLSHDN CL = 15pF, SW = VCC 25 - 60 - ns
Receiver Enable from Shutdown to
Output High
tZHSHDN CL = 15pF, SW = GND 25 - 20 - ns
RS-485 DRIVER SWITCHING CHARACTERISTICS (FAST DATA RATE (20Mbps), SEL = VCC, ALL VERSIONS (SPA = VCC if QFN))
Driver Differential Input to Output
Delay
tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2) Full 10 20 35 ns
Driver Output Skew tSKEW RDIFF = 54, CL = 100pF (Figure 2) Full - 2 10 ns
Driver Differential Rise or Fall Time tR, tFRDIFF = 54, CL = 100pF, (Figure 2) Full 3 20 30 ns
Driver Enable to Output Low tZL CL = 100pF, SW = VCC (Figure 3) Full - 28 60 ns
Driver Enable to Output High tZH CL = 100pF, SW = GND (Figure 3) Full - 35 60 ns
Driver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 3) Full - 30 60 ns
Driver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 3) Full - 30 60 ns
Driver Enable from Shutdown to
Output Low
tZL(SHDN) RL = 500, CL = 100pF, SW = VCC (Figure 3) Full - 100 250 ns
Driver Enable from Shutdown to
Output High
tZH(SHDN) RL = 500, CL = 100pF, SW = GND (Figure 3) Full - 290 375 ns
Driver Maximum Data Rate fMAX RDIFF = 54, CL = 100pF (Figure 2) Full 20 35 - Mbps
RS-485 DRIVER SWITCHING CHARACTERISTICS (MEDIUM DATA RATE (460kbps, QFN ONLY), SEL = VCC, SPA = SPB= GND)
Driver Differential Input to Output
Delay
tDLH, tDHL RDIFF = 54, CL = 100pF (Figure 2) Full 200 500 1000 ns
Driver Output Skew tSKEW RDIFF = 54, CL = 100pF (Figure 2) Full - 10 150 ns
Driver Differential Rise or Fall Time tR, tFRDIFF = 54, CL = 100pF (Figure 2) Full 300 660 1100 ns
Driver Enable to Output Low tZL CL = 100pF, SW = VCC (Figure 3) Full - 42 100 ns
Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 - C4 = 0.1µF, VL = VCC (for QFN only); Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA =+25°C (Note 7) (Continued)
PARAMETER SYMBOL TEST CONDITIONS
TEMP
(°C)
MIN
(Note 11) TYP
MAX
(Note 11) UNITS
ISL3332, ISL3333
FN6362 Rev 0.00 Page 10 of 26
May 27, 2008
Driver Enable to Output High tZH CL = 100pF, SW = GND (Figure 3) Full - 350 450 ns
Driver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 3) Full - 30 60 ns
Driver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 3) Full - 30 60 ns
Driver Enable from Shutdown to
Output Low
tZL(SHDN) RL = 500, CL = 100pF, SW = VCC (Figure 3) Full - - 500 ns
Driver Enable from Shutdown to
Output High
tZH(SHDN) RL = 500, CL = 100pF, SW = GND (Figure 3) Full - - 750 ns
Driver Maximum Data Rate fMAX RDIFF = 54, CL = 100pF (Figure 2) Full 460 2000 - kbps
RS-485 DRIVER SWITCHING CHARACTERISTICS (SLOW DATA RATE (115kbps, QFN ONLY), SEL = VCC, SPA = GND, SPB= VCC)
Driver Differential Input to Output
Delay
tDLH, tDHL RDIFF = 54, CL = 100pF (Figure2) Full 800 1600 2500 ns
Driver Output Skew tSKEW RDIFF = 54, CL = 100pF (Figure2) Full - 250 500 ns
Driver Differential Rise or Fall Time tR, tFRDIFF = 54, CL = 100pF (Figure 2) Full 1000 1700 3100 ns
Driver Enable to Output Low tZL CL = 100pF, SW = VCC (Figure 3) Full - 45 100 ns
Driver Enable to Output High tZH CL = 100pF, SW = GND (Figure 3) Full - 900 1200 ns
Driver Disable from Output Low tLZ CL = 15pF, SW = VCC (Figure 3) Full - 35 60 ns
Driver Disable from Output High tHZ CL = 15pF, SW = GND (Figure 3) Full - 25 60 ns
Driver Enable from Shutdown to
Output Low
tZL(SHDN) RL = 500, CL = 100pF, SW = VCC (Figure 3) Full - - 800 ns
Driver Enable from Shutdown to
Output High
tZH(SHDN) RL = 500, CL = 100pF, SW = GND (Figure 3) Full - - 1500 ns
Driver Maximum Data Rate fMAX RDIFF = 54, CL = 100pF (Figure 2) Full 115 800 - kbps
RS-485 RECEIVER SWITCHING CHARACTERISTICS (SEL = VCC, ALL VERSIONS AND SPEEDS)
Receiver Input to Output Delay tPLH, tPHL (Figure 4) Full 20 45 70 ns
Receiver Skew | tPLH - tPHL | tSKEW (Figure 4) Full - 3 10 ns
Receiver Maximum Data Rate fMAX Full 20 40 - Mbps
Receiver Enable to Output Low tZL QFN Only, CL = 15pF, SW = VCC (Figure 5) Full - 20 60 ns
Receiver Enable to Output High tZH QFN Only, CL = 15pF, SW = GND (Figure5) Full - 20 60 ns
Receiver Disable from Output Low tLZ QFN Only, CL = 15pF, SW = VCC (Figure 5) Full - 20 60 ns
Receiver Disable from Output High tHZ QFN Only, CL = 15pF, SW = GND (Figure 5) Full - 20 60 ns
Receiver Enable from Shutdown to
Output Low
tZLSHDN CL = 15pF, SW = VCC (Figure 5) Full - 500 900 ns
Receiver Enable from Shutdown to
Output High
tZHSHDN CL = 15pF, SW = GND (Figure 5) Full - 500 900 ns
NOTES:
7. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless
otherwise specified.
8. Supply current specification is valid for loaded drivers when DE = 0V (RS-485 mode) or DEN = 0V (RS-232 mode).
9. Applies to peak current. See “Typical Performance Curves” for more information.
10. RIN defaults to RS-485 mode (>15k) when the device is unpowered (VCC = 0V), or in SHDN, regardless of the state of the SEL inputs.
11. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by
characterization and are not production tested.
Electrical Specifications Test Conditions: VCC = 3.15V to 3.45V, C1 - C4 = 0.1µF, VL = VCC (for QFN only); Unless Otherwise Specified.
Typicals are at VCC = 3.3V, TA =+25°C (Note 7) (Continued)
PARAMETER SYMBOL TEST CONDITIONS
TEMP
(°C)
MIN
(Note 11) TYP
MAX
(Note 11) UNITS
ISL3332, ISL3333
FN6362 Rev 0.00 Page 11 of 26
May 27, 2008
Test Circuits and Waveforms
FIGURE 1. RS-485 DRIVER VOD AND VOC TEST CIRCUIT
FIGURE 2A. TEST CIRCUIT FIGURE 2B. MEASUREMENT POINTS
FIGURE 2. RS-485 DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES
D
DE
DY
VCC
VOD
VOC
R
R
Y
Z
R
D
D
DE
DY
VCC
SIGNAL
GENERATOR
CL = 100pF
RDIFF
Y
ZCL = 100pF
OUT (Z)
3V
0V
tPLH
1.5V1.5V
VOH
VOL
50% 50%
tPHL
OUT (Y)
tPHL
VOH
VOL
50% 50%
tPLH
DIFF OUT (Z - Y)
tR
+VOD
-VOD
90% 90%
tF
10% 10%
DY
SKEW = |tPLH (Y or Z) - tPHL (Z or Y)|
0V 0V
tDHL
tDLH
ISL3332, ISL3333
FN6362 Rev 0.00 Page 12 of 26
May 27, 2008
FIGURE 3A. TEST CIRCUIT FIGURE 3B. MEASUREMENT POINTS
FIGURE 3. RS-485 DRIVER ENABLE AND DISABLE TIMES
FIGURE 4A. TEST CIRCUIT FIGURE 4B. MEASUREMENT POINTS
FIGURE 4. RS-485 RECEIVER PROPAGATION DELAY
FIGURE 5A. TEST CIRCUIT FIGURE 5B. MEASUREMENT POINTS
FIGURE 5. RS-485 RECEIVER ENABLE AND DISABLE TIMES
Test Circuits and Waveforms (Continued)
D
DE
DY
CL
500
Y
Z
VCC
GND
SW
FOR SHDN TESTS, SWITCH ON/OFF RATHER THAN DE
PARAMETER ON/DE OUTPUT DY SW CL (pF)
tHZ 1/- Y/Z 0/1 GND 15
tLZ 1/- Y/Z 1/0 VCC 15
tZH 1/- Y/Z 0/1 GND 100
tZL 1/- Y/Z 1/0 VCC 100
tZH(SHDN) -/1 Y/Z 0/1 GND 100
tZL(SHDN) -/1 Y/Z 1/0 VCC 100
SIGNAL
GENERATOR
OUT (Y, Z)
3V
0V
1.5V1.5V
VOH
0V
2.3V
VOH - 0.5V
tHZ
OUT (Y, Z)
VCC
VOL
2.3V VOL + 0.5V
tLZ
DE
OUTPUT HIGH
OUTPUT LOW
tZL
tZH
tZH(SHDN)
tZL(SHDN)
(ON/OFF FOR SHDN)
ENABLED
SIGNAL
GENERATOR
RRA
RXEN (QFN ONLY)
B
A
0V
15pF
RA
+1.5V
-1.5V
tPLH
0V0V
VCC
0V
1.5V 1.5V
tPHL
B
1kVCC
GND
SW
FOR SHDN TESTS, SWITCH ON/OFF RATHER THAN RXEN
PARAMETER ON/RXEN BSW
tHZ (QFN Only) 1/- +1.5V GND
tLZ (QFN Only) 1/- -1.5V VCC
tZH (QFN Only) 1/- +1.5V GND
tZL (QFN Only) 1/- -1.5V VCC
tZH(SHDN) -/0 +1.5V GND
tZL(SHDN) -/0 -1.5V VCC
SIGNAL
GENERATOR
RRA
B
A
15pF
RXEN (QFN ONLY)
RA
3V
0V
1.5V1.5V
VOH
0V
1.5V
VOH - 0.5V
tHZ
RA
VCC
VOL
1.5V VOL + 0.5V
tLZ
RXEN (QFN ONLY)
OUTPUT HIGH
OUTPUT LOW
tZL
tZH
tZL(SHDN)
tZH(SHDN)
3V
0V
1.5V
ON/OFF
(FOR SHDN TESTS)
ENABLED
ISL3332, ISL3333
FN6362 Rev 0.00 Page 13 of 26
May 27, 2008
FIGURE 6A. TEST CIRCUIT FIGURE 6B. MEASUREMENT POINTS
FIGURE 6. RS-232 DRIVER PROPAGATION DELAY AND TRANSITION TIMES
FIGURE 7A. TEST CIRCUIT FIGURE 7B. MEASUREMENT POINTS
FIGURE 7. RS-232 RECEIVER PROPAGATION DELAY AND TRANSITION TIMES
Test Circuits and Waveforms (Continued)
D
DEN (QFN ONLY)
DY,Z
VCC
SIGNAL
GENERATOR
RL
Y, Z CL
OUT (Y,Z)
3V
0V
1.5V1.5V
VO+
VO-
0V 0V
DY,Z
SKEW = |tDPHL - tDPLH|
tDPHL tDPLH
R
RXEN (QFN ONLY)
A, B
SIGNAL
GENERATOR
RA, RBCL = 15pF
RA, RB
3V
0V
tRPHL
50%50%
VOH
VOL
50% 50%
tRPLH
A, B
SKEW = |tRPHL - tRPLH|
ISL3332, ISL3333
FN6362 Rev 0.00 Page 14 of 26
May 27, 2008
Typical Application
RS-232 to RS-485 Converter
The ISL3332, ISL3333 are ideal for implementing a single IC
2-wire (Tx Data, Rx Data) protocol converter, because each
port can be programmed for a different protocol. Figure 8
illustrates the simple connections to create a single
transceiver RS-232 to RS-485 converter. Depending on the
RS-232 data rate, using an RS-422 bus as an RS-232
“extension cord” can extend the transmission distance up to
4000’ (1220m). A similar circuit on the other end of the cable
completes the conversion to/from RS-232.
Detailed Description
Each of the two ISL333X ports supports dual protocols:
RS-485/422, and RS-232. RS-485 and RS-422 are differential
(balanced) data transmission standards for use in high speed
(up to 20Mbps) networks, or long haul and noisy
environments. The differential signaling, coupled with
RS-485’s requirement for an extended common mode range
(CMR) of +12V to -7V make these transceivers extremely
tolerant of ground potential differences, as well as voltages
induced in the cable by external fields. Both of these effects
are real concerns when communicating over the RS-485/422
maximum distance of 4000’ (1220m). It is important to note
that the ISL333X don’t follow the RS-485 convention
whereby the inverting I/O is labeled “B/Z”, and the non
inverting I/O is “A/Y”. Thus, in the application diagrams
below the 333X A/Y (B/Z) pins connect to the B/Z (A/Y)
pins of the generic RS-485/RS-422 ICs.
RS-422 is typically a point-to-point (one driver talking to one
receiver on a bus), or a point-to-multipoint (multidrop)
standard that allows only one driver and up to 10 receivers
on each bus. Because of the one driver per bus limitation,
RS-422 networks use a two bus, full duplex structure for
bidirectional communication, and the Rx inputs and Tx
outputs (no tri-state required) connect to different busses, as
shown in Figure 10.
Conversely, RS-485 is a true multipoint standard, which
allows up to 32 devices (any combination of drivers- must be
tri-statable - and receivers) on each bus. Now bidirectional
communication takes place on a single bus, so the Rx inputs
and Tx outputs of a port connect to the same bus lines, as
shown in Figure 9. Each port set to RS-485 /422 mode
includes one Rx and one Tx.RS-232 is a point-to-point,
singled ended (signal voltages referenced to GND)
communication protocol targeting fairly short (<150’, 46m)
and low data rate (<1Mbps) applications. Each port contains
two transceivers (2 Tx and 2 Rx) in RS-232 mode. Protocol
selection is handled via a logic pin (SELX) for each port.
26
VCC
Y1
Z1
DY1
DZ1
0.1µF
+
0.1µF
+
0.1µF
22
23
6
7
1
2
3
15
V+
V-
C1+
C1-
C2+
C2-
+
0.1µF
28
27
RA1
A1
4
5k
RB1
B1
525
5k
C1
C2
+C3
C4
GND
+3.3V +0.1µF
14
SEL1
ON/OFF
8
20 VCC
24
R
R
D
D
NOTE: PINOUT FOR SSOP
Y2
Z2
DY2 19
11
10
DE2 18 VCC
D
RA2
A2
13
B2
12 17
R
SEL2
9
VCC
RS-232 IN
RS-232 OUT
RS-485 IN
RS-485 OUT
NC
NC
NC
FIGURE 8. SINGLE IC RS-232 TO RS-485 CONVERTER
TxD
RxD
FIGURE 9. TYPICAL HALF DUPLEX RS-485 NETWORK
0.1µF
+
D
R
VCC
GND
RA
RXEN *
DE
DY
Y
Z
+3.3V
RT
0.1µF+
D
R
VCC
GND
RO
RE
DE
DI
A/Y
B/Z
+5V
0.1µF
+
D
VCC GND
RO RE DE DI
A/Y
B/Z
+5V
R
RT
ISL333X
GENERIC 1/2 DUPLEX 485 XCVR
GENERIC 1/2 DUPLEX 485 XCVR
Tx/Rx
* QFN ONLY
A
B
ISL3332, ISL3333
FN6362 Rev 0.00 Page 15 of 26
May 27, 2008
.
ISL333x Advan ta g es
These dual protocol ICs offer many parametric
improvements vs those offered on competing dual protocol
devices. Some of the major improvements are:
3.3V Supply Voltage - Eliminates the 5V supply that
powers just the interface IC
15kV Bus Pin ESD - Eases board level requirements
Full Failsafe RS-485 Rx - Eliminates bus biasing
Selectable RS-485 Data Rate - Up to 20Mbps, or slew
rate limited for low EMI and fewer termination issues
High RS-232 Data Rate - >250kbps
Lower Tx and Rx Skews - Wider, consistent bit widths
Lower ICC - Max ICC is 2x to -4x lower than competition
Flow-Thru Pinouts - Tx, Rx bus pins on one side/logic
pins on the other, for easy routing to connector/UART
Packaging - Smaller (QFN) and Pb-free.
RS-232 Mode
Rx Features
RS-232 receivers invert and convert RS-232 input levels
(3V to 25V) to the standard TTL/CMOS levels required by
a UART, ASIC, or µcontroller serial port. Receivers are
designed to operate at faster data rates than the drivers, and
they feature very low skews (18ns) so the receivers
contribute negligibly to bit width distortion. Inputs include the
standards required 3k to 7k pull-down resistor, so unused
inputs may be left unconnected. Rx inputs also have built-in
hysteresis to increase noise immunity, and to decrease
erroneous triggering due to slowly transitioning input signals.
Rx outputs are short circuit protected, and are only
tristatable when the entire IC is shutdown (SHDN) via the
ON/OFF pin, or via the active low RXEN pins available on
the QFN package option (see “ISL3333 Special Features” for
more details).
Tx Features
RS-232 drivers invert and convert the standard TTL/CMOS
levels from a UART, or µcontroller serial port to RS-232
compliant levels (5V minimum). The Tx delivers these
compliant output levels even at data rates of 400kbps, with
loads of 500pF, and with one output in each port switching at
this high rate. The drivers are designed for low skew
(typically 12% of the 400kbps bit width), and are compliant to
the RS-232 slew rate spec (4 to 30V/s) for a wide range of
load capacitances. Tx inputs float if left unconnected, and
may cause ICC increases. For the best results, connect
unused inputs to GND.
Tx outputs are short circuit protected, and incorporate a
thermal SHDN feature to protect the IC in situations of
severe power dissipation - see the RS-485 section for more
details. All drivers disable in SHDN, or when the 3.3V power
supply is off, and a port’s drivers also disable via the
corresponding DENX pin (see “ISL3333 Special Features”
for more details) available on the QFN package option (see
Tables 2 and 3 and the “Low Power Shutdown” section). The
ISL3332’s SHDN function is useful for disabling the outputs if
both ports will always be disabled together (e.g., used as a
four transceiver RS-232 port), and if it is acceptable for the
Rx to be disabled as well.
Charge Pumps
The on-chip charge pumps create the RS-232 transmitter
power supplies (typically +5.7/-5.3V) from a single supply as
low as 3.15V, and are enabled only if either port is
configured for RS-232 operation. The efficient design
requires only four small 0.1F capacitors for the voltage
doubler and inverter functions. By operating discontinuously
(i.e., turning off as soon as V+ and V- pump up to the
FIGURE 10. TYPICAL RS-422 NETWORK
0.1µF
+
D
R
VCC
GND
RA
DE
DY
B
A
+3.3V
0.1µF+
D
R
VCC
GND
RO
DI
A
Z
+5V
0.1µF
+
VCC GND
RO RE
+5V
R
RT
ISL333X (MASTER)
GENERIC 422 Rx (SLAVE)
GENERIC FULL DUPLEX 422 XCVR (SLAVE)
A
B
RT
Y
Z
YB
1k
OR NC
ISL3332, ISL3333
FN6362 Rev 0.00 Page 16 of 26
May 27, 2008
nominal values), the charge pump contribution to RS-232
mode ICC is reduced significantly. Unlike competing devices
that require the charge pump in RS-485 mode, disabling the
charge pump saves power, and minimizes noise. If the
application keeps both ports in RS-485 mode (e.g., a
dedicated dual channel RS-485 interface), then the charge
pump capacitors aren’t even required.
Data Rates and Cabling
Drivers operate at data rates up to 400kbps, and are
guaranteed for data rates up to 250kbps. The charge pumps
and drivers are designed such that one driver in each port
can be operated at the rated load, and at 250kbps (see
Figure 34). Figure 34 also shows that drivers can easily drive
two to three thousand picofarads at data rates up to
250kbps, while still delivering compliant 5V output levels.
Receivers operate at data rates up to 2Mbps. They are
designed for a higher data rate to facilitate faster factory
downloading of software into the final product, thereby
improving the user’s manufacturing throughput.
Figures 37 and 38 illustrate driver and receiver waveforms at
250kbps, and 500kbps, respectively. For these graphs, one
driver of each port drives the specified capacitive load, and a
receiver in the port.
RS-232 doesn’t require anything special for cabling; just a
single bus wire per transmitter and receiver, and another
wire for GND. So an ISL333X RS-232 port uses a five
conductor cable for interconnection. Bus terminations are
not required, nor allowed, by the RS-232 standard.
RS-485 Mode
Rx Features
RS-485 receivers convert differential input signals as small
as 200mV, as required by the RS-485 and RS-422
standards, to TTL/CMOS output levels. The differential Rx
provides maximum sensitivity, noise immunity, and common
mode rejection. Per the RS-485 standard, receiver inputs
function with common mode voltages as great as +12V and
-7V, regardless of supply voltage, making them ideal for long
networks where induced voltages are a realistic concern.
Each RS-485/RS-422 port includes a single receiver (RA),
and the unused Rx output (RB) is disabled but pulled high by
an internal current source. The internal current source turns
off in SHDN.
Worst case receiver input currents are 20% lower than the 1
“unit load” (1mA) RS-485 limit, which translates to a 15k
minimum input resistance.
These receivers include a “full fail-safe” function that
guarantees a high level receiver output if the receiver inputs
are unconnected (floating), shorted together, or if the bus is
terminated but undriven (i.e., differential voltage collapses to
near zero due to termination). Failsafe with shorted, or
terminated and undriven inputs is accomplished by setting
the Rx upper switching point at -40mV, thereby ensuring that
the Rx recognizes a 0V differential as a high level.
All the Rx outputs are short circuit protected, and are tri-state
when the IC is forced into SHDN, but ISL3332 (SSOP)
receiver outputs are not independently tri-statable. ISL3333
(QFN) receiver outputs are tri-statable via an active low
RXEN input for each port (see “ISL3333 Special Features”
for more details).
Tx Features
The RS-485/RS-422 driver is a differential output device that
delivers at least 1.5V across a 54 load (RS-485), and at
least 2V across a 100 load (RS-422). The drivers feature
low propagation delay skew to maximize bit widths, and to
minimize EMI.
To allow multiple drivers on a bus, the RS-485 spec requires
that drivers survive worst case bus contentions undamaged.
The ISL333X drivers meet this requirement via driver output
short circuit current limits, and on-chip thermal shutdown
circuitry. The output stages incorporate current limiting
circuitry that ensures that the output current never exceeds
the RS-485 spec, even at the common mode voltage range
extremes of 12V and -7V. In the event of a major short circuit
condition, devices also include a thermal shutdown feature
that disables the drivers whenever the die temperature
becomes excessive. This eliminates the power dissipation,
allowing the die to cool. The drivers automatically re-enable
after the die temperature drops about 15 degrees. If the
contention persists, the thermal shutdown/re-enable cycle
repeats until the fault is cleared. Receivers stay operational
during thermal shutdown.
RS-485 multi-driver operation also requires drivers to include
tri-state functionality, so each port has a DE pin to control
this function. If the driver is used in an RS-422 network, such
that driver tri-state isn’t required, then the DE pin can be left
unconnected and an internal pull-up keeps it in the enabled
state. Drivers are also tri-stated when the IC is in SHDN, or
when the 3.3V power supply is off.
Speed Options
The ISL3332 (SSOP) has fixed, high slew rate driver outputs
optimized for 20Mbps data rates. The ISL3333 (QFN) offers
three user selectable data rate options: “Fast” for high slew
rate and 20Mbps; “Medium” with slew rate limiting set for
460kbps; “Slow” with even more slew rate limiting for
115kbps operation. See the “Data Rate“ and “Slew Rate
Limited Data Rates” sections for more information.
Receiver performance is the same for all three speed
options.
Data Rate, Cables, and Terminations
RS-485/RS-422 are intended for network lengths up to 4000’
(1220m), but the maximum system data rate decreases as
the transmission length increases. Devices operating at the
maximum data rate of 20Mbps are limited to maximum
lengths of 20-100’ (6-31m), while devices operating at or
ISL3332, ISL3333
FN6362 Rev 0.00 Page 17 of 26
May 27, 2008
below 115kbps can operate at the maximum length of 4000’
(1220m).
Higher data rates require faster edges, so both the ISL333X
versions offer an edge rate capable of 20Mbps data rates.
The ISL3333 also offers two slew rate limited edge rates to
minimize problems at slower data rates. Nevertheless, for
the best jitter performance when driving long cables, the
faster speed settings may be preferable, even at low data
rates. See the “RS-485 Slew Rate Limited Data Rates”
section for details.
Twisted pair is the cable of choice for RS-485/RS-422
networks. Twisted pair cables tend to pick up noise and
other electromagnetically induced voltages as common
mode signals, which are effectively rejected by the
differential receivers in these ICs.
The preferred cable connection technique is “daisy-
chaining”, where the cable runs from the connector of one
device directly to the connector of the next device, such that
cable stub lengths are negligible. A “backbone” structure,
where stubs run from the main backbone cable to each
device’s connector, is the next best choice, but care must be
taken to ensure that each stub is electrically “short”. See
Table 4 for recommended maximum stub lengths for each
speed option.
Proper termination is imperative to minimize reflections
when using the 20Mbps speed option. Short networks using
the medium and slow speed options need not be terminated,
but terminations are recommended unless power dissipation
is an overriding concern. Note that the RS-485 spec allows a
maximum of two terminations on a network, otherwise the Tx
output voltage may not meet the required VOD.
In point-to-point, or point-to-multipoint (RS-422) networks,
the main cable should be terminated in its characteristic
impedance (typically 120) at the end farthest from the
driver. In multi-receiver applications, stubs connecting
receivers to the main cable should be kept as short as
possible, but definitely shorter than the limits shown in Table
4. Multipoint (RS-485) systems require that the main cable
be terminated in its characteristic impedance at both ends.
Again, keep stubs connecting a transceiver to the main
cable as short as possible, and refer to Table 4. Avoid “star”,
and other configurations, where there are many “ends”
which would require more than the two allowed terminations
to prevent reflections.
High ESD
All pins on the ISL333X include ESD protection structures
rated at 2.5kV (HBM), which is good enough to survive
ESD events commonly seen during manufacturing. But the
bus pins (Tx outputs and Rx inputs) are particularly
vulnerable to ESD events because they connect to an
exposed port on the exterior of the finished product. Simply
touching the port pins, or connecting a cable, can destroy an
unprotected port. ISL333X bus pins are fitted with advanced
structures that deliver ESD protection in excess of 15kV
(HBM), without interfering with any signal in the RS-485 or
the RS-232 range. This high level of protection may
eliminate the need for board level protection, or at the very
least will increase the robustness of any board level scheme.
Small Packages
Competing 3.3V dual protocol ICs are available only in a 28
Ld SSOP. The ISL3333’s tiny 6x6mm QFN footprint is 80%
smaller than the competing SSOP.
Flow Through Pinouts
Even the ISL333X pinouts are features, in that the true
flow-through design simplifies board layout. Having the bus
pins all on one side of the package for easy routing to a
cable connector, and the Rx outputs and Tx inputs (logic
pins) on the other side for easy connection to a UART,
avoids costly and problematic crossovers. Competing “flow
through” pinouts mix logic and bus pin inputs on one side of
the package, and logic and bus pin outputs on the other side.
This forces the designer to route four traces from the right
side of the IC around the IC to the cable connector. Figure 11
illustrates the flow-through nature of the ISL333X’s pinout.
Low Power Shutdown (SHDN) Mode
The ON/OFF pin is driven low to place the IC (both ports) in
the SHDN mode, and the already low supply current drops to
as low as 21A. If this functionality isn’t desired, the pin can
be left disconnected (thanks to the internal pull-up), or it
should be connected to VCC (VL for the QFN), through a
1k resistor. SHDN disables the Tx and Rx outputs, and
disables the charge pumps if either port is in RS-232 mode,
so V+ collapses to VCC, and V- collapses to GND.
TABLE 4. RECOMMENDED STUB LENGTHS
SPEED OPTION
MAXIMUM STUB LENGTH
ft (m)
SLOW 350-500 (107-152)
MED 100-150 (30.5 - 46)
FAST 1-3 (0.3 - 0.9)
UART
OR
ASIC
OR
µCONTROLLER
RA2
DY2
RA1
DY1
Z2
Y2
Y1
Z1
A1
B1
A2
B2
CONNECTOR
ISL3332
FIGURE 11. ILLUSTRATION OF FLOW THROUGH PINOUT
D
R
ISL3332, ISL3333
FN6362 Rev 0.00 Page 18 of 26
May 27, 2008
All but 10uA of SHDN supply current (ICC plus IL) is due to
control input (ON, LB, SP, DE, DEN) pull-up resistors
(~11A/resistor), so SHDN supply current varies depending
on the ISL333X configuration. The spec tables indicate the
SHDN currents for configurations that optimize these
currents. For example, in RS-232 mode the SP pins aren’t
used, so if both ports are configured for RS-232, floating or
tying the SP pins high minimizes SHDN current. Likewise in
RS-485 mode, the drivers are disabled in SHDN, so driving
the DE and DEN pins high during this time also reduces the
supply current.
When enabling from SHDN in RS-232 mode, allow at least
25s for the charge pumps to stabilize before transmitting
data. The charge pumps aren’t used in RS-485 mode, so the
transceiver is ready to send or receive data in less than 2µs,
which is much faster than competing devices that require the
charge pump for all modes of operation.
Internal Loopback Mode
Driving the LB pin low places both ports in the loopback
mode, a mode that facilitates implementing board level self
test functions. In loopback, internal switches disconnect the
Rx inputs from the Rx outputs, and feed back the Tx outputs
to the appropriate Rx output. This way the data driven at the
Tx input appears at the corresponding Rx output (refer to
“Typical Operating Circuits” on page 6”). The Tx outputs
remain connected to their terminals, so the external loads
are reflected in the loopback performance. This allows the
loopback function to potentially detect some common bus
faults such as one or both driver outputs shorted to GND, or
outputs shorted together.
Note that the loopback mode uses an additional set of
receivers, as shown in the “Typical Operating Circuits”.
These loopback receivers are not standards compliant, so
the loopback mode can’t be used to implement a half-duplex
RS-485 transceiver.
If loopback won’t be utilized, the pin can be left disconnected
(thanks to the internal pull-up), or it should be connected to
VCC (VL for the QFN), through a 1k resistor.
ISL3333 (QFN Package) Special Features
Logic Supply (VL Pin)
The ISL3333 (QFN) includes a VL pin that powers the logic
inputs (Tx inputs and control pins) and Rx outputs. These
pins interface with “logic” devices such as UARTs, ASICs,
and controllers, and today most of these devices use power
supplies significantly lower than 3.3V. Thus, a 3.3V output
level from a 3.3V powered dual protocol IC might seriously
overdrive and damage the logic device input. Similarly, the
logic device’s low VOH might not exceed the VIH of a 3.3V
powered dual protocol input. Connecting the VL pin to the
power supply of the logic device (Figure 12) limits the
ISL3333’s Rx output VOH to VL (Figure 15), and reduces the
Tx and control input switching points to values compatible
with the logic device output levels. Tailoring the logic pin
input switching points and output levels to the supply voltage
of the UART, ASIC, or controller eliminates the need for a
level shifter/translator between the two ICs.
VL can be anywhere from VCC down to 1.2V, but the input
switching points may not provide enough noise margin when
VL< 1.5V. Table 5 indicates typical VIH and VIL values for
various VL voltages so the user can ascertain whether or not
a particular VL voltage meets his needs.
Note: With VL 1.6V, the ISL3333 may not operate at the full
data rate unless the logic signal VIL is at least 0.2V below
the typical value listed in Table 5.
The VL supply current (IL) is typically less than 80A, even in
the worst case configuration, as shown in Figures 20 and 21.
With the Rx outputs unloaded, all of the DC VL current is due
to inputs with internal pull-up resistors (DE, DEN, SP, LB,
TABLE 5. VIH AND VIL vs. VL FOR VCC = 3.3V
VL (V) VIH (V) VIL (V)
1.2 0.85 0.26
1.5 0.9 0.5
1.8 0.9 0.73
2.3 1.2 1.0
2.7 1.4 1.3
3.3 1.8 1.7
FIGURE 12. USING VL PIN TO ADJUST LOGIC LEVELS
GND
RXD
TXD
VCC = +2V
UART/PROCESSOR
GND
RA
DY
VCC = +3.3V
ISL3332
VOH 2
VOH = 3.3V
VIH 2
ESD
DIODE
GND
RXD
TXD
VCC = +2V
UART/PROCESSOR
GND
RA
DY
VCC = +3.3V
ISL3333
VOH 2
VOH = 2V
VIH = 1V
ESD
DIODE
VL
ISL3332, ISL3333
FN6362 Rev 0.00 Page 19 of 26
May 27, 2008
ON/OFF) being driven to the low input state. The worst case
IL current occurs during SHDN (see Figure 21), due to the IL
through the ON/OFF pin pull-up resistor when that pin is
driven low. IIL through an input pull-up resistor is ~11µA (6µA
for DE1 and DE2), so the IL in Figure 20 drops by about
22µA (at VL= 3.3V) when the two SP inputs are high versus
low (next to bottom vs. top curve). SHDN IL is lowest in the
RS-232 mode, because only the DEN pins and/or the
ON/OFF pin should be driven low. When all the inputs with
pull-downs are driven high, IL drops to <<1µA (see Figure
20), so to minimize power dissipation drive these inputs high
when unneeded (e.g., SP inputs aren’t used in RS-232
mode, and DEN inputs aren’t used in RS-485 mode, so drive
them high in those modes).
QFN logic input pins that are externally tied high in an
application, should use the VL supply for the high voltage
level.
RS-232 Mode Tx Enable/Disable (DEN)
The ISL3333 also adds an RS-232 mode Tx enable pin
(DENX) for each port. Driving one of these pins low disables
both drivers in the corresponding port. Because RS-232 is a
point-to-point (only one Tx allowed on the bus) standard, the
main use for this disable function is to reduce power by
eliminating the load current (approximately 1mA per Tx
output) through the 5k resistor in the Rx at the cable’s far
end. The ICC in this mode is still considerably higher than in
SHDN, but the enable time from Tx disable is much faster
(1.5µs vs. 25µs) than the enable time from SHDN due to the
charge pumps remaining on during Tx disable.
The DENX pin is ignored if the corresponding port is set for
RS-485 mode, and it is internally pulled high.
Active Low Rx Enable (RXEN)
In many RS-485 applications, especially half duplex
configurations, users like to accomplish “echo cancellation”
by disabling the corresponding receiver while its driver is
transmitting data. This function is available on the QFN
package via an active low RXEN pin for each port. The
active low function also simplifies direction control, by
allowing a single Tx/Rx direction control line. If an active high
RXEN were used, either two valuable I/O pins would be
used for direction control, or an external inverter is required
between DE and RXEN. Figure 13 details the advantage of
using the RXEN pin.
RS-485 Slew Rate Limited Data Rates
The SSOP version of this IC operates with Tx output
transitions optimized for a 20Mbps data rate. These fast
edges may increase EMI and reflection issues, even though
fast transitions aren’t required at the lower data rates used
by many applications. The ISL3333 (QFN version) solves
this problem by offering two additional, slew rate limited,
data rates that are optimized for speeds of 115kbps, and
460kbps.The slew limited edges permit longer unterminated
networks, or longer stubs off terminated busses, and help
minimize EMI and reflections. Nevertheless, for the best jitter
performance when driving long cables, the faster speed
options may be preferable, even at lower data rates. The
faster output transitions deliver less variability (jitter) when
loaded with the large capacitance associated with long
cables. Of course, faster transitions require more attention to
ensuring short stub lengths and quality terminations, so
there are trade-offs to be made. Assuming a jitter budget of
10%, it is likely better to go with the slow speed option for
data rates of 115kbps or less, to minimize fast edge effects.
Likewise, the medium speed option is a good choice for data
rates between 115kbps and 460kbps. For higher data rates,
or when the absolute best jitter is required, use the high
speed option. Speed selection is via the SPA and SPB pins
(see Table 3), and the selection pertains to each port
programmed for RS-485 mode.
Evaluation Board
An evaluation board, part number ISL3333EVAL1Z, is
available to assist in assessing the dual protocol IC’s
performance. The evaluation board contains a QFN
packaged device, but because the same die is used in all
packages, the board is also useful for evaluating the
functionality of the other versions. The board’s design allows
for evaluation of all standard features, plus the QFN specific
features. Refer to the eval board application note for details,
and contact your sales rep for ordering information.
FIGURE 13. USING ACTIVE LOW vs ACTIVE HIGH RX
ENABLE
0.1µF
+
D
R
VCC
GND
RA
RXEN
DEN
DY
+3.3V
ISL3330
Tx/Rx
ACTIVE HIGH RX ENABLE
0.1µF
+
D
R
VCC
GND
RA
RXEN *
DE
DY
+3.3V
ISL3333
Tx/Rx
* QFN ONLY
ACTIVE LOW RX ENABLE
Y
Z
A
B
Y
Z
A
B
ISL3332, ISL3333
FN6362 Rev 0.00 Page 20 of 26
May 27, 2008
Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified
FIGURE 14. RECEIVER OUTPUT CURRENT vs RECEIVER
OUTPUT VOLTAGE
FIGURE 15. RECEIVER HIGH OUTPUT VOLTAGE vs LOGIC
SUPPLY VOLTAGE (VL) (QFN ONLY)
FIGURE 16. RS-485, DRIVER OUTPUT CURRENT vs
DIFFERENTIAL OUTPUT VOLTAGE
FIGURE 17. RS-485, DRIVER DIFFERENTIAL OUTPUT
VOLTAGE vs TEMPERATURE
FIGURE 18. RS-485, DRIVER OUTPUT CURRENT vs SHORT
CIRCUIT VOLTAGE
FIGURE 19. SUPPLY CURRENT vs TEMPERATURE
RECEIVER OUTPUT VOLTAGE (V)
RECEIVER OUTPUT CURRENT (mA)
0
5.0
10
15
20
25
30
0
VOH, +25 °C
VOH, +85 °C
VOL, +25 °C
VOL, +85 °C
1233.3
VL (V)
HIGH OUTPUT VOLTAGE (V)
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
1 1.5 2.0 2.5 3.0
IOH = -1mA
IOH = -2mA
IOH = -6mA
IOH = -0.5mA
3.3
DIFFERENTIAL OUTPUT VOLTAGE (V)
DRIVER OUTPUT CURRENT (mA)
0
10
20
30
40
50
60
70
80
90
00.511.522.533.5
-40 0 50 85
TEMPERATURE (°C)
DIFFERENTIAL OUTPUT VOLTAGE (V)
-25 25 75
1.9
1.95
2.00
2.05
2.10
2.15
2.20
2.25
2.30
RDIFF = 54
RDIFF = 100
OUTPUT VOLTAGE (V)
-7 -6 -4 -2 0 2 4 6 8 10 12
OUTPUT CURRENT (mA)
-150
-100
-50
0
50
100
150
200
250
Y OR Z = HIGH
Y OR Z = LOW
+25 °C
+85 °C
-40 °C
+25 °C
+85 °C
-40 °C
-40 0 50 85
TEMPERATURE (°C)
ICC (mA)
-25 25 75
1
1.5
2.0
2.5
3.0
3.5
4.0
4.5
RS-232, RXEN = X, DEN = VL (IF QFN)
RS-485, DE = GND, RXEN = X
RS-485, HALF DUPLEX, DE = VCC, RXEN = X
RS-232, DEN = GND, RXEN = X (QFN ONLY)
RS-485, FULL DUPLEX, DE = VCC, RXEN = X
ISL3332, ISL3333
FN6362 Rev 0.00 Page 21 of 26
May 27, 2008
FIGURE 20. VL SUPPLY CURRENT vs VL VOLTAGE (QFN
ONLY)
FIGURE 21. VCC and VL SHDN SUPPLY CURRENTS vs VL
VOLTAGE (QFN ONLY)
FIGURE 22. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (SLOW DATA RATE, QFN ONLY)
FIGURE 23. RS-485, DRIVER SKEW vs TEMPERATURE
(SLOW DATA RATE, QFN ONLY)
FIGURE 24. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (MEDIUM DATA RATE, QFN
ONLY)
FIGURE 25. RS-485, DRIVER SKEW vs TEMPERATURE
(MEDIUM DATA RATE, QFN ONLY)
Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
0
10
20
30
40
50
60
1 1.5 2.0 2.5 3.0 3.5 4.0
IL (µA)
VL (V)
VL VCC VL > VCC
RS-232, DEN = SP = VL
RS-485, DE = GND, SP = DEN = V
L
RS-485, DE = SP = GND, DEN = VL
NO LOAD
VIN = VL or GND
LB = ON = VL, RXEN = GND
RS-232, DEN = GND, SP = V
L
0
10
20
30
40
50
60
70
80
90
100
1 1.5 2.02.5 3.03.5 4.0
ICC and IL (µA)
VL (V)
NO LOAD
VIN = VL or GND
LB = VL
ON = DZ/DE = DY = GND
RS-232/RS-485 ICC
RS-485 I
L
, SP = DEN = GND
RS-232 I
L
, SP = DEN = GND
RS-485 I
L
, SP = GND, DEN = V
L
RS-232 I
L
, SP = V
L
, DEN = GND
RS-232 I
L
, SP = DEN = VL
1550
1560
1570
1580
1590
1600
1610
1620
1630
1640
-40 0 50 85
TEMPERATURE (°C)
-25 25 75
PROPAGATION DELAY (ns)
tDLH
tDHL
RDIFF = 54, CL = 100pF
tDHL
0
50
100
150
200
250
300
-40 0 50 85
TEMPERATURE (°C)
SKEW (ns)
-25 25 75
|tPLHZ - tPHLY|
|tPHLZ - tPLHY|
|tDLH - tDHL|
RDIFF = 54, CL = 100pF
-40 0 50 85
TEMPERATURE (°C)
-25 25 75
PROPAGATION DELAY (ns)
tDLH
tDHL
tDHL
RDIFF = 54, CL = 100pF
515
520
525
530
535
540
545
550
-40 0 50 85
TEMPERATURE (°C)
SKEW (ns)
-25 25 75
0
2
4
6
8
10
12
14
16 RDIFF = 54, CL = 100pF
|tPHLZ - tPLHY|
|tPLHZ - tPHLY|
|tDLH - tDHL|
ISL3332, ISL3333
FN6362 Rev 0.00 Page 22 of 26
May 27, 2008
FIGURE 26. RS-485, DRIVER PROPAGATION DELAY vs
TEMPERATURE (FAST DATA RATE)
FIGURE 27. RS-485, DRIVER SKEW vs TEMPERATURE
(FAST DATA RATE)
FIGURE 28. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (SLOW DATA RATE, QFN ONLY)
FIGURE 29. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (SLOW DATA RATE, QFN ONLY)
FIGURE 30. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (MEDIUM DATA RATE, QFN ONLY)
FIGURE 31. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (MEDIUM DATA RATE, QFN ONLY)
Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
-40 0 50 85
TEMPERATURE (°C)
-25 25 75
PROPAGATION DELAY (ns)
15
16
17
18
19
20
21
22
23
24
tDLH
RDIFF = 54, CL = 100pF
tDHL
0
0.5
1.0
1.5
2.0
2.5
3.0
-40 0 50 85
TEMPERATURE (°C)
SKEW (ns)
-25 25 75
RDIFF = 54, CL = 100pF
|tPLHZ - tPHLY|
|tPHLZ - tPLHY|
|tDLH - tDHL|
TIME (400ns/DIV)
DY
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
0
5
0
5
DRIVER INPUT (V)
RDIFF = 54, CL = 100pF
RA
Z
Y
0
1
2
3
4
TIME (400ns/DIV)
DY
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
0
5
0
5
DRIVER INPUT (V)
RDIFF = 54, CL = 100pF
RA
Z
Y
0
1
2
3
4
TIME (200ns/DIV)
DY
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
0
5
0
5
DRIVER INPUT (V)
RDIFF = 54, CL = 100pF
RA
Z
Y
0
1
2
3
4
TIME (200ns/DIV)
DY
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
0
5
0
5
DRIVER INPUT (V)
RDIFF = 54, CL = 100pF
RA
0
1
2
3
4
Z
Y
ISL3332, ISL3333
FN6362 Rev 0.00 Page 23 of 26
May 27, 2008
FIGURE 32. RS-485, DRIVER AND RECEIVER WAVEFORMS,
LOW TO HIGH (FAST DATA RATE)
FIGURE 33. RS-485, DRIVER AND RECEIVER WAVEFORMS,
HIGH TO LOW (FAST DATA RATE)
FIGURE 34. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
LOAD CAPACITANCE
FIGURE 35. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
TEMPERATURE
FIGURE 36. RS-232, TRANSMITTER SHORT CIRCUIT
CURRENT vs TEMPERATURE
FIGURE 37. RS-232, TRANSMITTER AND RECEIVER
WAVEFORMS AT 250kbps
Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
TIME (10ns/DIV)
DY
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
0
5
0
5
DRIVER INPUT (V)
RDIFF = 54, CL = 100pF
RA
Z
Y
0
1
2
3
4
TIME (10ns/DIV)
DY
RECEIVER OUTPUT (V)
DRIVER OUTPUT (V)
0
5
0
5
DRIVER INPUT (V)
RDIFF = 54, CL = 100pF
RA
0
1
2
3
4
Z
Y
-7.5
-5
-2.5
2.5
7.5
1000 2000 3000 4000 50000
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
RS-232 REGION OF NONCOMPLIANCE
0
5.0
2 TRANSMITTERS AT 250kbps or 400kbps,
VOUT+
VOUT -
OTHER TRANSMITTERS AT 30kbps
400kbps
400kbps
250kbps
250kbps
ALL TOUTS LOADED WITH 3k TO GND
-40 0 50 85
TEMPERATURE (°C)
TRANSMITTER OUTPUT VOLTAGE (V)
-25 25 75
-7.5
-5
0
5.0
7.5
2.5
-2.5
VOUT+
VOUT -
OUTPUTS STATIC
ALL TOUTS LOADED WITH 3k TO GND
AND AT V+ OR V-
-40 0 50 85
TEMPERATURE (°C)
TRANSMITTER OUTPUT CURRENT (mA)
-25 25 75
-30
-20
-10
0
10
20
30
40
50
Y or Z = HIGH
Y or Z = LOW
VOUT SHORTED TO GND
2µs/DIV.
CL = 2000pF, 2 CHANNELS SWITCHING
Y/A
0
-5
0
5
0
5
5
RA
DY
ISL3332, ISL3333
FN6362 Rev 0.00 Page 24 of 26
May 27, 2008
FIGURE 38. RS-232, TRANSMITTER AND RECEIVER
WAVEFORMS AT 400kbps
FIGURE 39. RS-232, RECEIVER OUTPUT +DUTY CYCLE vs
DATA RATE
FIGURE 40. RS-232, TRANSMITTER MAXIMUM DATA RATE vs
LOAD CAPACITANCE
FIGURE 41. RS-232, TRANSMITTER OUTPUT VOLTAGE vs
DATA RATE
FIGURE 42. RS-232, TRANSMITTER SKEW vs DATA RATE
Die Characteristics
SUBSTRATE AND QFN PAD POTENTIAL
(POWERED UP):
GND
TRANSISTOR COUNT:
4838
PROCESS:
BiCMOS
Typical Performance Curves VCC = VL = 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)
2µs/DIV.
CL = 1000pF, 2 CHANNELS SWITCHING
Y/A
0
-5
0
5
0
5
5
RA
DY
49
50
51
52
53
54
55
56
57
58
0 500 1000 1500 2000
DATA RATE (kbps)
RECEIVER + DUTY CYCLE (%)
FULL TEMP RANGE
SR IN = 15V/µs
SR IN = 100V/µs
VIN = 5V
0 1000 2000 3000 4000 5000
100
150
200
250
300
350
400
450
500
550
LOAD CAPACITANCE (pF)
DATA RATE (kbps)
2 TRANSMITTERS AT +85°C
1 TRANSMITTER AT +25°C
V
OUT

4V AND DUTY CYCLE BETWEEN 40% AND 60%
ALL TOUTS LOADED WITH 5k TO GND
1 TRANSMITTER AT +85°C
2 TRANSMITTERS AT +25°C
0 100 200 300 400 500 600
-7.5
-5
0
5
7.5
2.5
-2.5
DATA RATE (kbps)
TRANSMITTER OUTPUT VOLTAGE (V)
+25°C
+85°C
+25°C
+85°C
VOUT -
2 TRANSMITTERS SWITCHING
ALL TOUTS LOADED WITH 5k TO GND, CL = 1000pF
RS-232 REGION OF NONCOMPLIANCE
VOUT+
250
300
350
400
450
500
550
600
650
DATA RATE (kbps)
SKEW (ns)
0 200 400 600 650
+25°C
+85°C
-40 °C
ALL TOUTS LOADED WITH 3k TO GND, CL = 1000pF
2 TRANSMITTERS SWITCHING
50
FN6362 Rev 0.00 Page 25 of 26
May 27, 2008
ISL3332, ISL3333
Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil may modify the circuit design and/or specifications of products at any time without notice, provided that such
modification does not, in Intersil's sole judgment, affect the form, fit or function of the product. Accordingly, the reader is cautioned to verify that datasheets are
current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its
subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
For additional products, see www.intersil.com/en/products.html
© Copyright Intersil Americas LLC 2008. All Rights Reserved.
All trademarks and registered trademarks are the property of their respective owners.
Shrink Small Outline Plastic Packages (SSOP)
NOTES:
1. Symbols are defined in the “MO Series Symbol List” in Section 2.2
of Publication Number 95.
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
3. Dimension “D” does not include mold flash, protrusions or gate
burrs. Mold flash, protrusion and gate burrs shall not exceed
0.20mm (0.0078 inch) per side.
4. Dimension “E” does not include interlead flash or protrusions.
Interlead flash and protrusions shall not exceed 0.20mm (0.0078
inch) per side.
5. The chamfer on the body is optional. If it is not present, a visual
index feature must be located within the crosshatched area.
6. “L” is the length of terminal for soldering to a substrate.
7. “N” is the number of terminal positions.
8. Terminal numbers are shown for reference only.
9. Dimension “B” does not include dambar protrusion. Allowable
dambar protrusion shall be 0.13mm (0.005 inch) total in excess of
“B” dimension at maximum material condition.
10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.
INDEX
AREA
E
D
N
123
-B-
0.25(0.010) C AMBS
e
-A-
L
B
M
-C-
A1
A
SEATING PLANE
0.10(0.004)
C
H0.25(0.010) BM M
0.25
0.010
GAUGE
PLANE
A2
M28.209 (JEDEC MO-150-AH ISSUE B)
28 LEAD SHRINK SMALL OUTLINE PLASTIC PACKAGE
SYMBOL
INCHES MILLIMETERS
NOTESMIN MAX MIN MAX
A - 0.078 - 2.00 -
A1 0.002 - 0.05 - -
A2 0.065 0.072 1.65 1.85 -
B 0.009 0.014 0.22 0.38 9
C 0.004 0.009 0.09 0.25 -
D 0.390 0.413 9.90 10.50 3
E 0.197 0.220 5.00 5.60 4
e 0.026 BSC 0.65 BSC -
H 0.292 0.322 7.40 8.20 -
L 0.022 0.037 0.55 0.95 6
N28 287
-
Rev. 2 6/05
ISL3332, ISL3333
FN6362 Rev 0.00 Page 26 of 26
May 27, 2008
Package Outline Drawing
L40.6x6
40 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
Rev 3, 10/06
located within the zone indicated. The pin #1 identifier may be
Unless otherwise specified, tolerance : Decimal ± 0.05
Tiebar shown (if present) is a non-functional feature.
The configuration of the pin #1 identifier is optional, but must be
between 0.15mm and 0.30mm from the terminal tip.
Dimension b applies to the metallized terminal and is measured
Dimensions in ( ) for Reference Only.
Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
6.
either a mold or mark feature.
3.
5.
4.
2.
Dimensions are in millimeters.1.
NOTES:
(4X) 0.15
INDEX AREA
PIN 1
A
6.00
B
6.00
31
36X 0.50
4.5
4X
40 PIN #1 INDEX AREA
BOTTOM VIEW
40X 0 . 4 ± 0 . 1
20
B0.10
11
MAC
4
21
4 . 10 ± 0 . 15
0 . 90 ± 0 . 1 C
SEATING PLANE
BASE PLANE
0.08
0.10
SEE DETAIL "X"
C
C
0 . 00 MIN.
DETAIL "X"
0 . 05 MAX.
0 . 2 REF
C5
SIDE VIEW
1
10
30
TYPICAL RECOMMENDED LAND PATTERN
( 5 . 8 TYP )
( 4 . 10 )
( 36X 0 . 5 )
( 40X 0 . 23 )
( 40X 0 . 6 )
6
6
TOP VIEW
0 . 23 +0 . 07 / -0 . 05