LM146/LM346
Programmable Quad Operational Amplifiers
General Description
The LM146 series of quad op amps consists of four inde-
pendent, high gain, internally compensated, low power, pro-
grammable amplifiers. Two external resistors (R
SET
) allow
the user to program the gain bandwidth product, slew rate,
supply current, input bias current, input offset current and
input noise. For example, the user can trade-off supply
current for bandwidth or optimize noise figure for a given
source resistance. In a similar way, other amplifier charac-
teristics can be tailored to the application. Except for the two
programming pins at the end of the package, the LM146
pin-out is the same as the LM124 and LM148.
Features
(I
SET
=10 µA)
nProgrammable electrical characteristics
nBattery-powered operation
nLow supply current: 350 µA/amplifier
nGuaranteed gain bandwidth product: 0.8 MHz min
nLarge DC voltage gain: 120 dB
nLow noise voltage: 28
nWide power supply range: ±1.5V to ±22V
nClass AB output stage–no crossover distortion
nIdeal pin out for Biquad active filters
nInput bias currents are temperature compensated
Connection Diagram
Dual-In-Line Package
00565401
Top View
Order Number LM146J, LM146J/883,
LM346M,LM346MX or LM346N
See NS Package Number
J16A, M16A or N16A
PROGRAMMING EQUATIONS
Total Supply Current = 1.4 mA (I
SET
/10 µA)
Gain Bandwidth Product = 1 MHz (I
SET
/10 µA)
Slew Rate = 0.4V/µs (I
SET
/10 µA)
Input Bias Current .50 nA (I
SET
/10 µA)
I
SET
= Current into pin 8, pin 9 (see schematic-diagram)
Capacitorless Active Filters (Basic Circuit)
00565416
August 2000
LM146/LM346 Programmable Quad Operational Amplifiers
© 2004 National Semiconductor Corporation DS005654 www.national.com
Absolute Maximum Ratings (Notes 1,
5)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
LM146 LM346
Supply Voltage ±22V ±18V
Differential Input Voltage (Note 1) ±30V ±30V
CM Input Voltage (Note 1) ±15V ±15V
Power Dissipation (Note 2) 900 mW 500 mW
Output Short-Circuit Duration (Note 3) Continuous Continuous
Operating Temperature Range −55˚C to +125˚C 0˚C to +70˚C
Maximum Junction Temperature 150˚C 100˚C
Storage Temperature Range −65˚C to +150˚C −65˚C to +150˚C
Lead Temperature (Soldering, 10 seconds) 260˚C 260˚C
Thermal Resistance (θ
jA
), (Note 2)
Cavity DIP (J) Pd 900 mW 900 mW
θ
jA
100˚C/W 100˚C/W
Small Outline (M) θ
jA
115˚C/W
Molded DIP (N) Pd 500 mW
θ
jA
90˚C/W
Soldering Information
Dual-In-Line Package
Soldering (10 seconds) +260˚C +260˚C
Small Outline Package
Vapor Phase (60 seconds) +215˚C +215˚C
Infrared (15 seconds) +220˚C +220˚C
See AN-450 “Surface Mounting Methods and Their Effect on
Product Reliability” for other methods of soldering surface
mount devices.
ESD rating is to be determined.
DC Electrical Characteristics
(V
S
=±15V, I
SET
=10 µA), (Note 4)
Parameter Conditions LM146 LM346 Units
Min Typ Max Min Typ Max
Input Offset Voltage V
CM
=0V, R
S
≤50Ω,T
A
=25˚C 0.5 5 0.5 6 mV
Input Offset Current V
CM
=0V, T
A
=25˚C 2 20 2 100 nA
Input Bias Current V
CM
=0V, T
A
=25˚C 50 100 50 250 nA
Supply Current (4 Op Amps) T
A
=25˚C 1.4 2.0 1.4 2.5 mA
Large Signal Voltage Gain R
L
=10 kΩ,∆V
OUT
=±10V, 100 1000 50 1000 V/mV
T
A
=25˚C
Input CM Range T
A
=25˚C ±13.5 ±14 ±13.5 ±14 V
CM Rejection Ratio R
S
≤10 kΩ,T
A
=25˚C 80 100 70 100 dB
Power Supply Rejection Ratio R
S
≤10 kΩ,T
A
=25˚C, 80 100 74 100 dB
V
S
=±5to±15V
Output Voltage Swing R
L
≥10 kΩ,T
A
=25˚C ±12 ±14 ±12 ±14 V
Short-Circuit T
A
=25˚C 5 20 35 5 20 35 mA
Gain Bandwidth Product T
A
=25˚C 0.8 1.2 0.5 1.2 MHz
Phase Margin T
A
=25˚C 60 60 Deg
Slew Rate T
A
=25˚C 0.4 0.4 V/µs
Input Noise Voltage f=1 kHz, T
A
=25˚C 28 28
Channel Separation R
L
=10 kΩ,∆V
OUT
=0V to 120 120 dB
LM146/LM346
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DC Electrical Characteristics (Continued)
(V
S
=±15V, I
SET
=10 µA), (Note 4)
Parameter Conditions LM146 LM346 Units
Min Typ Max Min Typ Max
±12V, T
A
=25˚C
Input Resistance T
A
=25˚C 1.0 1.0 MΩ
Input Capacitance T
A
=25˚C 2.0 2.0 pF
Input Offset Voltage V
CM
=0V, R
S
≤50Ω0.5 6 0.5 7.5 mV
Input Offset Current V
CM
=0V 2 25 2 100 nA
Input Bias Current V
CM
=0V 50 100 50 250 nA
Supply Current (4 Op Amps) 1.7 2.2 1.7 2.5 mA
Large Signal Voltage Gain R
L
=10 kΩ,∆V
OUT
=±10V 50 1000 25 1000 V/mV
Input CM Range ±13.5 ±14 ±13.5 ±14 V
CM Rejection Ratio R
S
≤50Ω70 100 70 100 dB
Power Supply Rejection Ratio R
S
≤50Ω, 76 100 74 100 dB
V
S
=±5V to ±15V
Output Voltage Swing R
L
≥10 kΩ±12 ±14 ±12 ±14 V
DC Electrical Characteristic
(V
S
=±15V, I
SET
=10 µA)
Parameter Conditions LM146 LM346 Units
Min Typ Max Min Typ Max
Input Offset Voltage V
CM
=0V, R
S
≤50Ω, 0.5 5 0.5 7 mV
T
A
=25˚C
Input Bias Current V
CM
=0V, T
A
=25˚C 7.5 20 7.5 100 nA
Supply Current (4 Op Amps) T
A
=25˚C 140 250 140 300 µA
Gain Bandwidth Product T
A
=25˚C 80 100 50 100 kHz
DC Electrical Characteristics
(V
S
=±1.5V, I
SET
=10 µA)
Parameter Conditions LM146 LM346 Units
Min Typ Max Min Typ Max
Input Offset Voltage V
CM
=0V, R
S
≤50Ω, 0.5 5 0.5 7 mV
T
A
=25˚C
Input CM Range T
A
=25˚C ±0.7 ±0.7 V
CM Rejection Ratio R
S
≤50Ω,T
A
=25˚C 80 80 dB
Output Voltage Swing R
L
≥10 kΩ,T
A
=25˚C ±0.6 ±0.6 V
Note 1: For supply voltages less than ±15V, the absolute maximum input voltage is equal to the supply voltage.
Note 2: The maximum power dissipation for these devices must be derated at elevated temperatures and is dictated by TjMAX,θjA, and the ambient temperature,
TA. The maximum available power dissipation at any temperature is Pd=(TjMAX -T
A)/θjA or the 25˚C PdMAX, whichever is less.
Note 3: Any of the amplifier outputs can be shorted to ground indefinitely; however, more than one should not be simultaneously shorted as the maximum junction
temperature will be exceeded.
Note 4: These specifications apply over the absolute maximum operating temperature range unless otherwise noted.
Note 5: Refer to RETS146X for LM146J military specifications.
LM146/LM346
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Typical Performance Characteristics
Input Bias Current vs I
SET
Supply Current vs I
SET
00565444 00565445
Open Loop Voltage Gain
vs I
SET
Slew Rate vs I
SET
00565446
00565447
Gain Bandwidth Product
vs I
SET
Phase Margin vs I
SET
00565448 00565449
LM146/LM346
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Typical Performance Characteristics (Continued)
Input Offset Voltage
vs I
SET
Common-Mode Rejection
Ratio vs I
SET
00565450 00565451
Power Supply Rejection
Ratio vs I
SET
Open Voltage Swing vs
Supply Voltage
00565452 00565453
Input Voltage Range vs
Supply Voltage
Input Bias Current vs
Input Common-Mode
Voltage
00565454 00565455
LM146/LM346
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Typical Performance Characteristics (Continued)
Input Bias Current vs
Temperature
Input Offset Current vs
Temperature
00565456 00565457
Supply Current vs
Temperature
Open Loop Voltage Gain
vs Temperature
00565458
00565420
Gain Bandwidth Product
vs Temperature
Slew Rate vs
Temperature
00565421 00565422
LM146/LM346
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Typical Performance Characteristics (Continued)
Input Noise Voltage vs
Frequency
Input Noise Current vs
Frequency
00565423 00565424
Power Supply Rejection
Ratio vs Frequency
Voltage Follower Pulse
Response
00565425 00565426
Voltage Follower Transient
Response Transient Response Test Circuit
00565427
00565406
LM146/LM346
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Application Hints
Avoid reversing the power supply polarity; the device will fail.
COMMON-MODE INPUT VOLTAGE
The negative common-mode voltage limit is one diode drop
above the negative supply voltage. Exceeding this limit on
either input will result in an output phase reversal. The
positive common-mode limit is typically 1V below the posi-
tive supply voltage. No output phase reversal will occur if this
limit is exceeded by either input.
OUTPUT VOLTAGE SWING VS I
SET
For a desired output voltage swing the value of the minimum
load depends on the positive and negative output current
capability of the op amp. The maximum available positive
output current, (I
CL+
), of the device increases with I
SET
whereas the negative output current (I
CL−
) is independent of
I
SET
.Figure 1 illustrates the above.
INPUT CAPACITANCE
The input capacitance, C
IN
, of the LM146 is approximately 2
pF; any stray capacitance, C
S
, (due to external circuit circuit
layout) will add to C
IN
. When resistive or active feedback is
applied, an additional pole is added to the open loop fre-
quency response of the device. For instance with resistive
feedback (Figure 2), this pole occurs at
1
⁄
2
π(R1||R2) (C
IN
+
C
S
). Make sure that this pole occurs at least 2 octaves
beyond the expected −3 dB frequency corner of the closed
loop gain of the amplifier; if not, place a lead capacitor in the
feedback such that the time constant of this capacitor and
the resistance it parallels is equal to the R
I
(C
S
+C
IN
), where
R
I
is the input resistance of the circuit.
TEMPERATURE EFFECT ON THE GBW
The GBW (gain bandwidth product), of the LM146 is directly
proportional to I
SET
and inversely proportional to the abso-
lute temperature. When using resistors to set the bias cur-
rent, I
SET
, of the device, the GBW product will decrease with
increasing temperature. Compensation can be provided by
creating an I
SET
current directly proportional to temperature
(see typical applications).
ISOLATION BETWEEN AMPLIFIERS
The LM146 die is isothermally layed out such that crosstalk
between all 4 amplifiers is in excess of −105 dB (DC).
Optimum isolation (better than −110 dB) occurs between
amplifiers A and D, B and C; that is, if amplifier A dissipates
power on its output stage, amplifier D is the one which will be
affected the least, and vice versa. Same argument holds for
amplifiers B and C.
LM146 TYPICAL PERFORMANCE SUMMARY
The LM146 typical behaviour is shown in Figure 3. The
device is fully predictable. As the set current, I
SET
, increases,
the speed, the bias current, and the supply current increase
while the noise power decreases proportionally and the V
OS-
remains constant. The usable GBW range of the op amp is
10 kHz to 3.5−4 MHz.
Low Power Supply Operation: The quad op amp operates
down to ±1.3V supply. Also, since the internal circuitry is
biased through programmable current sources, no degrada-
tion of the device speed will occur.
SPEED VS POWER CONSUMPTION
LM146 vs LM4250 (single programmable). Through Figure
4, we observe that the LM146’s power consumption has
been optimized for GBW products above 200 kHz, whereas
the LM4250 will reach a GBW of no more than 300 kHz. For
GBW products below 200 kHz, the LM4250 will consume
less power.
00565407
FIGURE 1. Output Current Limit vs I
SET
00565409
FIGURE 2.
00565408
FIGURE 3. LM146 Typical Characteristics
LM146/LM346
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Application Hints (Continued)
Typical Applications
Dual Supply or Negative Supply Blasing
00565439
Single (Positive) Supply Blasing
00565411
Current Source Blasing
with Temperature Compensation
00565440
•The LM334 provides an ISET directly proportional to absolute
temperature. This cancels the slight GBW product Temperature coefficient
of the LM346.
00565410
FIGURE 4. LM146 vs LM4250
LM146/LM346
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Typical Applications (Continued)
Blasing all 4 Amplifiers
with Single Current Source
00565441
•For ISET1.ISET2 resistors R1 and R2 are not required if a slight error between the 2 set currents can be tolerated. If not, then use R1 = R2 to create a 100
mV drop across these resistors.
Active Filters Applications
Basic (Non-Inverting “State Variable”) Active Filter Building Block
00565412
LM146/LM346
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Active Filters Applications (Continued)
00565433
Note. All resistor values are given in ohms.
00565413
00565434
00565435
LM146/LM346
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Active Filters Applications (Continued)
A Simple-to-Design BP, LP Filter Building Block
00565414
•If resistive biasing is used to set the LM346 performance, the Qoof this filter building block is nearly insensitive to the op amp’s GBW product temperature
drift; it has also better noise performance than the state variable filter.
Circuit Synthesis Equations
00565436
•For the eventual use of amplifier C, see comments on the previous page.
A 3-Amplifier Notch Filter (or Elliptic Filter Building Block)
00565415
Circuit Synthesis Equations
00565437
•For nothing but a notch output: RIN=R, C'=C.
LM146/LM346
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Active Filters Applications (Continued)
Capacitorless Active Filters (Basic Circuit)
00565416
00565438
1. Pick up a convenient value for b; (b <1)
2. Adjust Qothrough R5
3. Adjust Ho(BP) through R4
4. Adjust fothrough RSET. This adjusts the unity gain frequency (fu) of the op amp.
LM146/LM346
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Active Filters Applications (Continued)
A 4th Order Butterworth Low Pass Capacitorless Filter
00565417
Ex: fc= 20 kHz, Ho(gain of the filter) = 1, Q01 = 0.541, Qo2 = 1.306.
•Since for this filter the GBW product of all 4 amplifiers has been designed to be the same (∼1 MHz) only one current source can be used to bias the circuit.
Fine tuning can be further accomplished through Rb.
Miscellaneous Applications
A Unity Gain Follower
with Bias Current Reduction
00565418
•For better performance, use a matched NPN pair.
LM146/LM346
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Miscellaneous Applications (Continued)
Circuit Shutdown
00565442
•By pulling the SET pin(s) to V−the op amp(s) shuts down and its output goes to a high impedance state. According to this property, the LM346 can be used
as a very low speed analog switch.
Voice Activated Switch and Amplifier
00565443
LM146/LM346
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Miscellaneous Applications (Continued)
X10 Micropower Instrumentation Amplifier with Buffered Input Guarding
00565419
•CMRR: 100 dB (typ)
•Power dissipation: 0.4 mW
Schematic Diagram
00565402
LM146/LM346
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Physical Dimensions inches (millimeters)
unless otherwise noted
Cavity Dual-In-Line Package (J)
Order Number LM146J, LM146J/883
NS Package Number J16A
S.O. Package (M)
Order Number LM346M
NS Package Number M16A
LM146/LM346
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Molded Dual-In-Line Package (N)
Order Number LM346N
NS Package Number N16A
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can be reasonably expected to cause the failure of
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LM146/LM346 Programmable Quad Operational Amplifiers
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
