General Description
The MAX4236/MAX4237 are high-precision op amps
that feature an exceptionally low offset voltage and off-
set voltage temperature coefficient without using any
chopper techniques. The MAX4236 and MAX4237 have
a typical large-signal, open-loop voltage gain of 120dB.
These devices have an ultra-low input-bias current of
1pA. The MAX4236 is unity-gain stable with a gain-
bandwidth product of 1.7MHz, while the MAX4237 is
stable for closed-loop gains greater than 5V/V with a
gain-bandwidth product of 7.5MHz. Both devices have
a shutdown function in which the quiescent current is
reduced to less than 0.1µA, and the amplifier output is
forced into a high-impedance state.
The input common-mode range of the MAX4236/
MAX4237 extends below the negative supply range, and
the output swings Rail-to-Rail®. These features make the
amplifiers ideal for applications with +3V or +5V single
power supplies. The MAX4236/MAX4237 are specified for
the extended temperature range (-40°C to +85°C) and
are available in tiny SOT23, µMAX, and SO packages. For
greater accuracy, the A grade µMAX and SO packages
are tested to guarantee 20µV (max) offset voltage at
+25°C and less then 2µV/°C drift.
Applications
Strain Gauges
Piezoelectric Sensors
Thermocouple Amplifiers
Electrochemical Sensors
Battery-Powered Instrumentation
Instrumentation Amplifiers
Features
♦Ultra-Low Offset Voltage
20µV (max) at +25°C (Grade A)
50µV (max) at +25°C (Grade B, 6-Pin SOT23)
♦Ultra-Low Offset Voltage Drift
2µV/°C (max) (Grade A)
4.5µV/°C (max) (Grade B, 6-Pin SOT23)
5.5µV/°C (max) (6-Pin SOT23)
♦Ultra-Low 1pA Input Bias Current
♦High Open-Loop Voltage Gain: 110dB (min)
(RL= 100kΩ)
♦Compatible with +3V and +5V Single-Supply
Power Systems
♦Ground Sensing: Input Common-Mode Range
Includes Negative Rail
♦Rail-to-Rail Output Swing into a 1kΩLoad
♦350µA Quiescent Current
♦Gain-Bandwidth Product
1.7MHz (MAX4236, AV= 1V/V)
7.5MHz (MAX4237, AV= 5V/V)
♦200pF Capacitive Load Handling Capability
♦Shutdown Mode: 0.1µA Quiescent Current,
Places Output in a High-Impedance State
♦Available in Space-Saving SOT23 and µMAX
Packages
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-to-Rail Op Amps
________________________________________________________________ Maxim Integrated Products 1
TOP VIEW
VEE
IN-IN+
16VCC
5SHDN
OUT
MAX4236
MAX4237
SOT23-6
2
34
1
2
3
4
8
7
6
5
VCC
OUT
N.C.VEE
IN+
IN-
N.C.
MAX4236A/B
MAX4237A/B
SO-8/µMAX
SHDN
Pin Configurations
Ordering Information
19-2110; Rev 0; 8/01
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP. RANGE PIN-PACKAGE
MAX4236EUT-T -40°C to +85°C 6 SOT23-6
MAX4236AEUA -40°C to +85°C 8 µMAX
MAX4236BEUA -40°C to +85°C 8 µMAX
MAX4236AESA -40°C to +85°C 8 SO
MAX4236BESA -40°C to +85°C 8 SO
MAX4237EUT-T -40°C to +85°C 6 SOT23-6
MAX4237AEUA -40°C to +85°C 8 µMAX
MAX4237BEUA -40°C to +85°C 8 µMAX
MAX4237AESA -40°C to +85°C 8 SO
MAX4237BESA -40°C to +85°C 8 SO
Rail-to-Rail is a registered trademark of Nippon Motorola, Inc.
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS (SO-8 and µMAX-8)
(VCC = +2.4V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC/2, RL= 100kΩto VCC/2, TA= TMIN to TMAX, unless otherwise noted. Typical
values are at VCC = +5V and TA= +25°C.) (Note 1)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Supply Voltage (VCC - VEE)......................................-0.3V to +6V
Analog Input Voltage (IN+ or IN-)....(VEE - 0.3V) to (VCC + 0.3V)
Logic Input Voltage (SHDN) ............(VEE - 0.3V) to (VCC + 0.3V)
Current into Any Pin ............................................................20mA
Output Short-Circuit Duration....Continuous to Either VCC or VEE
Continuous Power Dissipation (TA= +70°C)
6-Pin SOT23-6 (derate 8.7mW/°C above +70°C) .........696mW
8-Pin µMAX (derate 4.5mW/°C above +70°C) ..............362mW
8-Pin SO (derate 5.9mW/°C above +70°C)...................471mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range VCC Guaranteed by the PSRR test 2.4 5.5 V
In normal mode 350 440
VCC = +5V In shutdown mode 0.1 2
In normal mode 350 440
Quiescent Supply Current ICC
VCC = +3V In shutdown mode 0.1 2
µA
TA = +25oC ±5 ±20
VCC = +5V,
Grade A TA = TMIN to TMAX ±150
TA = +25oC ±5 ±50
Input Offset Voltage VOS VCC = +5V,
Grade B TA = TMIN to TMAX ±340
µV
Grade A ±0.6 ±2
Inp ut Offset V ol tag e Tem p er atur e
C oeffi ci ent TCVOS VCC = +5V
(Note 3) Grade B ±0.6 ±4.5 µV/°C
Input Bias Current IB(Note 2) ±1 ±500 pA
Input Offset Current IOS (Note 2) ±1 pA
Input Resistance RIN Differential or common mode 1000 MΩ
Input Common-Mode Voltage VCM Guaranteed by the CMRR test -0.15 V
C C
- 1.2 V
TA = +25oC 84 102
VCC = +5V;
-0.15V ≤ VCM ≤
(VCC - 1.2V) TA = TMIN to TMAX 80
TA = +25oC 82 102
Common-Mode Rejection Ratio CMRR VCC = +3.0V;
-0.15V ≤ VCM ≤
(VCC - 1.2V) TA = TMIN to TMAX 78
dB
TA = +25oC 97 120
Power-Supply Rejection Ratio PSRR VCC = +2.4V to
+5.5V TA = TMIN to TMAX 95 dB
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (SO-8 and µMAX-8) (continued)
(VCC = +2.4V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC/2, RL= 100kΩto VCC/2, TA= TMIN to TMAX, unless otherwise noted. Typical
values are at VCC = +5V and TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
RL = 100kΩ, VOUT =
15mV to (VCC - 50mV) 110 128
VCC = +5V, RL
connected to
VCC/2,
TA = +25oCRL = 1kΩ, VOUT =
0.15V to (VCC - 0.3V) 105 114
RL = 100kΩ, VOUT =
15mV to (VCC - 50mV) 110
VCC = +5V, RL
connected to
VCC/2,
TA = TMIN to
TMAX
RL = 1kΩ,
VOUT = 0.15V
to (VCC - 0.3V)
100
RL = 100kΩ, VOUT =
15mV to (VCC - 50mV) 110 128
VCC = +3V, RL
connected to
VCC/2,
TA = +25oC
RL = 1kΩ,
VOUT = 0.15V
to (VCC - 0.3V)
100 114
RL = 100kΩ, VOUT =
15mV to (VCC - 50mV) 105
Large-Signal Voltage Gain AVOL
VCC = +3V, RL
connected to
VCC/2,
TA = TMIN to
TMAX
RL = 1kΩ,
VOUT = 0.15V
to (VCC - 0.3V)
95
dB
VCC - VOH 210
VCC = +5V,
RL connected to VCC /2,
RL = 100kΩVOL - VEE 310
VCC - VOH 150 250
Output Voltage Swing VOUT
VCC = +5V,
RL connected to VCC/2,
RL = 1kΩVOL - VEE 50 100
mV
Shorted to VEE 10
Output Short-Circuit Current IOUT
(
SC
)
Shorted to VCC 30 mA
MAX4236 1.7
Gain-Bandwidth Product GBWP RL = ∞, CL = 5pF MAX4237 7.5 MHz
MAX4236 0.3
Slew Rate SR VCC = +5V, VOUT = 4V step MAX4237 1.3 V/µs
MAX4236 1
Settling Time tSVOUT settling to within
0.01% MAX4237 1 µs
Total Harmonic Distortion THD f = 5kHz, VOUT = 2Vp-p, VCC = +5V
RL = 10kΩ0.001 %
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
4 _______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (SO-8 and µMAX-8) (continued)
(VCC = +2.4V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC/2, RL= 100kΩto VCC/2, TA= TMIN to TMAX, unless otherwise noted. Typical
values are at VCC = +5V and TA= +25°C.) (Note 1)
ELECTRICAL CHARACTERISTICS (SOT23-6)
(VCC = +2.4V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC/2, RL= 100kΩto VCC/2, TA= TMIN to TMAX, unless otherwise noted. Typical
values are at VCC = +5V and TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Input Capacitance CIN f = 100kHz 7.5 pF
Input Voltage Noise Density enf = 1kHz 14 nV/√Hz
Input Noise Voltage enp-p f = 0.1Hz to 10Hz 0.2 µVp-p
MAX4236 200
Capacitive Load Stability CLOAD No sustained oscillations MAX4237 200 pF
Shutdown Mode Output
Leakage IOUT
(
SH
)
Device in shutdown mode (SHDN = VEE)
VOUT = 0 to VCC ±0.01 ±1.0 µA
SHDN Logic Low VIL 0.3 ✕
VCC V
SHDN Logic High VIH 0.7 ✕
VCC V
SHDN Input Current SHDN = VEE or VCC 13µA
Shutdown Delay Time t(SH) RL = 1kΩ1µs
Shutdown Recovery Time t(EN) RL = 1kΩ4µs
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range VCC Guaranteed by the PSRR test 2.4 5.5 V
In normal mode 350 440
VCC = +5V In shutdown mode 0.1 2
In normal mode 350 440
Quiescent Supply Current ICC
VCC = +3V In shutdown mode 0.1 2
µA
TA = +25°C ±5 ±50
Input Offset Voltage VOS VCC = +5V TA = TMIN to TMAX ±600 µV
Inp ut Offset V ol tag e Tem p er atur e
C oeffi ci ent ( N ote 2) TCVOS VCC = +5V ±0.6 ±5.5 µV/°C
Input Bias Current IB(Note 2) ±1 ±500 pA
Input Offset Current IOS (Note 2) ±1 pA
Input Resistance RIN Differential or common mode 1000 MΩ
Input Common-Mode Voltage VCM Guaranteed by the CMRR test -0.15 V
C C
- 1.2 V
TA = +25°C 82 102
VCC = +5V, -0.15V
≤ VCM ≤ (VCC - 1.2V) TA = TMIN to TMAX 80
TA = +25°C 82 102
Common-Mode Rejection Ratio CMRR VCC = +3.0V; -0.15V
≤ VCM ≤ (VCC - 1.2V) TA = TMIN to TMAX 78
dB
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (SOT23-6) (continued)
(VCC = +2.4V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC/2, RL= 100kΩto VCC/2, TA= TMIN to TMAX, unless otherwise noted. Typical
values are at VCC = +5V and TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
TA = +25°C 97 120
Power-Supply Rejection Ratio PSRR VCC = +2.4V to
+5.5V TA = TMIN to TMAX 95 dB
RL = 100kΩ,
VOUT = 15mV to
(VCC - 50mV)
110 128
VCC = +5V, RL
connected to
VCC/2,
TA = +25°C
RL = 1kΩ,
VOUT = 0.15V
to (VCC - 0.3V)
100 114
RL = 100kΩ, VOUT =
15mV to (VCC - 50mV) 110
VCC = +5V, RL
connected to
VCC/2,
TA = TMIN to
TMAX
RL = 1kΩ,
VOUT = 0.15V to
(VCC - 0.3V)
95
RL = 100kΩ,
VOUT = 15mV to
(VCC - 50mV)
110 128
VCC = +3V, RL
connected to
VCC/2,
TA = +25°C
RL = 1kΩ,
VOUT = 0.15V to
(VCC - 0.3V)
100 114
RL = 100kΩ,
VOUT = 15mV to
(VCC - 50mV)
105
Large-Signal Voltage Gain AVOL
VCC = +3V, RL
connected to
VCC/2,
TA = TMIN to
TMAX
RL = 1kΩ,
VOUT = 0.15V to
(VCC - 0.3V)
95
dB
VCC - VOH 210
VCC = +5V,
RL connected to VCC/2,
RL = 100kΩVOL - VEE 310
VCC - VOH 150 250
Output Voltage Swing VOUT
VCC = +5V,
RL connected to VCC/2,
RL = 1kΩVOL - VEE 50 100
mV
Shorted to VEE 10
Output Short-Circuit Current IOUT
(
SC
)
Shorted to VCC 30 mA
MAX4236 1.7
Gain-Bandwidth Product GBWP RL = ∞, CL = 15pF MAX4237 7.5 MHz
MAX4236 0.3
Slew Rate SR VCC = +5V,
VOUT = 4V step MAX4237 1.3 V/µs
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
6 _______________________________________________________________________________________
0
4
2
10
8
6
12
14
16
18
-10 -6 -4-8 -2 0 2 4 6 8 10
VOS DISTRIBUTION
MAX 4236 toc01
VOS (µV)
PERCENT OF UNITS (%)
VCC = 5V
0
5
15
10
20
25
TCVOS DISTRIBUTION
MAX4236 toc02
TCVOS (µV/°C)
PERCENT OF UNITS (%)
-
2.0
-
1.5 -1.0 -0.5 0 0.5 1.0 1.5 2.0
VCC = 5V
OFFSET VOLTAGE vs. TEMPERATURE
MAX4236 toc02
-80
-60
-20
-40
40
60
20
0
80
OFFSET VOLTAGE (µV)
-50 0 25-25 50 75 100 125
TEMPERATURE (°C)
Typical Operating Characteristics
(VCC = +5V, VEE = 0, VCM = VCC/2, RL= 100kΩto VCC/2, TA= +25°C, unless otherwise noted.)
ELECTRICAL CHARACTERISTICS (SOT23-6) (continued)
(VCC = +2.4V to +5.5V, VEE = 0, VCM = 0, VOUT = VCC/2, RL= 100kΩto VCC/2, TA= TMIN to TMAX, unless otherwise noted. Typical
values are at VCC = +5V and TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX4236 1
Settling Time tSVOUT settling to within 0.01% MAX4237 1 µs
Total Harmonic Distortion THD f = 5kHz, VOUT = 2Vp-p, VCC = +5V
RL = 10kΩ0.001 %
Input Capacitance CIN f = 100kHz 7.5 pF
Input Voltage Noise Density enf = 1kHz 14 nV/√Hz
Input Noise Voltage enp-p f = 0.1Hz to 10Hz 0.2 µVp-p
MAX4236 200
Capacitive Load Stability CLOAD No sustained oscillations MAX4237 200 pF
Shutdown Mode Output
Leakage IOUT
(
SH
)
Device in shutdown mode (SHDN = VEE)
VOUT = 0 to VCC ±0.01 ±1.0 µA
SHDN Logic Low VIL 0.3 x V
CC V
SHDN Logic High VIH 0.7 x V
CC V
SHDN Input Current SHDN = VEE or VCC 13µA
Shutdown Delay Time t(SH) RL = 1kΩ1µs
Shutdown Recovery Time t(EN) RL = 1kΩ4µs
Note 1: All devices are 100% production tested at TA= +25°C; all specifications over temperature are guaranteed by design,
unless otherwise specified.
Note 2: Guaranteed by design, not production tested.
Note 3: Maxim specification limits for the temperature coefficient of the offset voltage (TCVOS) are 100% tested for the A-grade, 8-
pin SO and µMAX packages.
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
_______________________________________________________________________________________ 7
0
40
20
80
60
120
100
140
03.0
COMMON-MODE REJECTION RATIO
vs. COMMON-MODE INPUT VOLTAGE
MAX4236 toc04
COMMON-MODE INPUT VOLTAGE (V)
COMMON-MODE REJECTION RATIO (dB)
2.0 2.51.51.00.5
VCC = 3V
COMMON-MODE REJECTION RATIO
vs. FREQUENCY (VCC = 5V)
MAX4236 toc06
FREQUENCY (kHz)
COMMON-MODE REJECTION RATIO (dB)
120
0
40
60
80
100
0.01 10 100 10000.1 1 10,000
20
COMMON-MODE REJECTION RATIO
vs. FREQUENCY (VCC = 3V)
MAX4236 toc07
FREQUENCY (kHz)
COMMON-MODE REJECTION RATIO (dB)
140
0
40
60
80
100
0.01 10 100 10000.1 1 10,000
20
120
120
0.1 1 10 100 1000 10,000
100
80
40
20
0
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY (VCC = 5V)
MAX4236 toc08
FREQUENCY (kHz)
PSSR (dB)
60
0.001 10 10000.10.01 1 100 10,000 100,000
MAX4237
OPEN-LOOP GAIN/PHASE
vs. FREQUENCY
MAX4236 toc09
FREQUENCY (kHz)
GAIN (dB)
-20
20
60
140
120
100
80
40
0
0
20
40
100
80
60
PHASE (DEGREES)
PHASE
GAIN
VCC = 5V/3V
CL = 15pF/200pF
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC/2, RL= 100kΩto VCC/2, TA= +25°C, unless otherwise noted.)
0.001 10 10000.10.01 1 100 10,000
MAX4236
OPEN-LOOP GAIN/PHASE
vs. FREQUENCY
MAX4236 toc10
FREQUENCY (kHz)
GAIN (dB)
-20
20
60
140
120
100
80
40
0
0
20
40
100
80
60
PHASE (DEGREES)
PHASE
GAIN
VCC = 5V/3V
CL = 15pF/200pF
25
20
15
10
5
0
0.01 1 100.1 100
INPUT VOLTAGE NOISE vs. FREQUENCY
MAX4236 toc11
FREQUENCY (kHz)
INPUT VOLTAGE NOISE (nV√Hz)
1
0.0001
10 100 10k 100k
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
0.001
0.01
0.1
MAX4236 toc12
FREQUENCY (Hz)
THD + NOISE (%)
1k
VOUT = 2Vp-p
0
40
20
80
60
120
100
140
021345
COMMON-MODE REJECTION RATIO
vs. COMMON-MODE INPUT VOLTAGE
MAX4236 toc05
COMMON-MODE INPUT VOLTAGE (V)
COMMON-MODE REJECTION RATIO (dB)
VCC = 5V
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
8 _______________________________________________________________________________________
300
330
320
310
350
340
390
380
370
360
400
-50 -25 0 25 50 75 100 125
SUPPLY CURRENT vs. TEMPERATURE
MAX4236 toc13
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
+V = 5V
+V = 3V
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC/2, RL= 100kΩto VCC/2, TA= +25°C, unless otherwise noted.)
315
325
320
335
330
340
345
2.5 3.5 4.03.0 4.5 5.0 5.5
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX4236 toc14
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
TA = -40°C
TA = +25°C
TA = +85°C
TA = +125°C
60
80
100
120
LARGE-SIGNAL GAIN vs. TEMPERATURE
MAX4236 toc15
TEMPERATURE (°C)
GAIN (dB)
140
-50 25 50-25 0 75 100 125
VCC = 5V, RL to VEE
VCC = 5V, RL to VCC
VCC = 3V, RL to VEE
VCC = 3V, RL to VCC
RL = 1kΩ
0
15
10
5
25
20
45
40
35
30
50
-50 -25 0 25 50 75 100 125
MINIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
MAX4236 toc16
TEMPERATURE (°C)
MINIMUM OUTPUT VOLTAGE (mV)
VCC = 5V, RL = 1kΩ
VCC = 3V, RL = 1kΩ
VCC = 5V/3V, RL = 100kΩ
0
60
40
20
100
80
180
160
140
120
200
-50 -25 0 25 50 75 100 125
MAXIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
MAX4236 toc17
TEMPERATURE (°C)
MAXIMUM OUTPUT VOLTAGE (mV)
VCC = 5V, RL = 1kΩ
VCC = 3V, RL = 1kΩ
VCC = 5V/3V, RL = 100kΩ
0
60
40
20
80
100
120
140
160
180
200
3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX4236 toc18
SUPPLY VOLTAGE (V)
OUTPUT VOLTAGE (mV)
RL = 1kΩ
VOL - VEE, RL to VEE
VCC - VOH, RL to VCC
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
3.0 3.5 4.0 4.5 5.0
OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX4236 toc19
SUPPLY VOLTAGE (V)
OUTPUT VOLTAGE (mV)
VOL - VEE
VCC - VOH
RL = 100kΩ
0
6
4
2
8
10
12
0 2.01.50.5 1.0 2.5 3.0 3.5 4.0 4.5 5.0
OUTPUT SOURCE CURRENT
vs. OUTPUT VOLTAGE
MAX4236 toc20
OUTPUT VOLTAGE (V)
OUTPUT SOURCE CURRENT (mA)
VCC = 5V
0
3
2
1
4
5
6
7
8
9
10
0 1.00.5 1.5 2.0 2.5 3.0
OUTPUT SOURCE CURRENT
vs. OUTPUT VOLTAGE
MAX4236 toc21
OUTPUT VOLTAGE (V)
OUTPUT SOURCE CURRENT (mA)
VCC = 3V
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
_______________________________________________________________________________________ 9
0
20
10
30
60
70
50
40
80
0 1.0 1.5 2.0 2.50.5 3.0 3.5 4.0 4.5 5.0
OUTPUT SINK CURRENT
vs. OUTPUT VOLTAGE
MAX4236 toc22
OUTPUT VOLTAGE (V)
OUTPUT SINK CURRENT (mA)
VCC = 5V
OUTPUT TO GND
0
20
10
40
30
50
60
0 1.0 1.50.5 2.0 2.5 3.0
OUTPUT SINK CURRENT
vs. OUTPUT VOLTAGE
MAX4236 toc23
OUTPUT VOLTAGE (V)
OUTPUT SINK CURRENT (mA)
VCC = 3V
OUTPUT TO GND
0
5
10
15
20
SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
MAX4236 toc24
TEMPERATURE (°C)
SHORT-CIRCUIT CURRENT (mA)
-50 25 50-25 0 75 100 125
VCC = 5V
VCC = 3V
SHORTED TO VEE
(SOURCING CURRENT)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC/2, RL= 100kΩto VCC/2, TA= +25°C, unless otherwise noted.)
SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
MAX4236 toc25
0
5
15
10
30
35
25
20
40
SHORT-CIRCUIT CURRENT (mA)
-50 0 25-25 50 75 100 125
TEMPERATURE (°C)
VCC = 5V
VCC = 3V
SHORTED TO VCC
(SINKING CURRENT)
-2.5
-1.0
-1.5
-2.0
-0.5
0
0.5
1.0
1.5
2.0
2.5
-100 -50 0 50 100
DC I/O TRANSFER CURVE
(RLOAD = 100kΩ)
MAX4236 toc26
DIFFERENTIAL INPUT VOLTAGE (µV)
OUTPUT VOLTAGE (V)
VSUPPLY = ±2.5V
-2.5
-1.0
-1.5
-2.0
-0.5
0
0.5
1.0
1.5
2.0
2.5
-100 -50 0 50 100
DC I/O TRANSFER CURVE
(RLOAD = 1kΩ)
MAX4236 toc27
DIFFERENTIAL INPUT VOLTAGE (µV)
OUTPUT VOLTAGE (V)
VSUPPLY = ±2.5V
1µs/div
MAX4236
NONINVERTING SMALL-SIGNAL RESPONSE
INPUT
10mV/div
OUTPUT
10mV/div
MAX4236 toc28
VCC = ±2.5V
RL = 1kΩ, CL = 15pF
AV = 1V/V
0
0
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
10 ______________________________________________________________________________________
2µs/div
MAX4237
NONINVERTING LARGE-SIGNAL RESPONSE
INPUT
200mV/div
OUTPUT
1V/div
MAX4236 toc30
VCC = ±2.5V
RL = 1kΩ, CL = 15pF
AV = 5V/V
0
0
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = 0, VCM = VCC/2, RL= 100kΩto VCC/2, TA= +25°C, unless otherwise noted.)
1µs/div
MAX4237
NONINVERTING LARGE-SIGNAL RESPONSE
INPUT
200mV/div
OUTPUT
1V/div
MAX4236 toc31
VCC = ±2.5V
RL = 100kΩ, CL = 15pF
AV = 5V/V
0
0
4µs/div
MAX4236
NONINVERTING LARGE-SIGNAL RESPONSE
INPUT
1V/div
OUTPUT
1V/div
MAX4236 toc32
VCC = ±2.5V
RL = 1kΩ, CL = 15pF
AV = 1V/V
0
0
4µs/div
MAX4236
NONINVERTING LARGE-SIGNAL RESPONSE
INPUT
1V/div
OUTPUT
1V/div
MAX4236 toc33
VCC = ±2.5V
RL = 100kΩ, CL = 15pF
AV = 1V/V
0
0
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
______________________________________________________________________________________ 11
Detailed Description
The MAX4236/MAX4237 are high-precision op amps
with a CMOS input stage and an excellent set of DC
and AC features. The combination of tight maximum
voltage offset, low offset tempco and very low input
current make them ideal for use in high-precision DC
circuits. They feature low-voltage operation, low-power
consumption, high-current drive with rail-to-rail output
swing and high-gain bandwidth product.
High Accuracy
The MAX4236/MAX4237 maximum input offset voltage
is 20µV (5µV, typ) for grade A version and 50µV for
grade B version at +25°C. The maximum temperature
coefficient of the offset voltage for grade A and B are
guaranteed to be 2µV/°C and 4.5µV/°C respectively.
The parts have an input bias current of 1pA. Noise
characteristics are 14nV/√Hz, and a low frequency
noise (0.1Hz to 10Hz) of 0.2µVp-p. The CMRR is
102dB, and the PSRR is 120dB. The combination is
what is necessary for the design of circuits to process
signals while keeping high signal-to-noise ratios, as in
stages preceding high-resolution converters, or when
they are produced by sensors or transducers generat-
ing very small outputs.
Rail-to-Rail Outputs, Ground-Sensing Input
The input common-mode range extends from (VEE -
0.15V) to (VCC - 1.2V) with excellent common-mode
rejection. Beyond this range, the amplifier output is a
nonlinear function of the input, but does not undergo
phase reversal or latch-up (see Typical Operating
Characteristics).
The output swings to within 150mV of the power-supply
rails with a 1kΩload. The input ground sensing and the
rail-to-rail output substantially increase the dynamic
range.
Power-Up and Shutdown Mode
The MAX4236/MAX4237 have a shutdown option.
When the shutdown pin (SHDN) is pulled low, the sup-
ply current drops to 0.1µA, and the amplifiers are dis-
abled with the output in a high-impedance state. Pulling
SHDN high enables the amplifiers. The turn-on time for
the amplifiers to come out of shutdown is 4µs.
Applications Information
As described above, the characteristics of the
MAX4236/MAX4237 are excellent for high-precision/
accuracy circuitry, and the high impedance, low-cur-
rent, low-offset, and noise specifications are very
attractive for piezoelectric transducers applications. In
these applications, the sensors generate an amount of
electric charge proportional to the changes in the
mechanical stress applied to them. These charges are
transformed into a voltage proportional to the applied
force by injecting them into a capacitance and then
amplifying the resulting voltage. The voltage is an
inverse function of the capacitance into which the
charges generated by the transducer/ sensor are
injected. This capacitance and the resistance that dis-
charges it, define the low-frequency response of the
circuit. It is desirable, once the preferred low-frequency
response is known, to maintain the capacitance as low
as possible, because the amount of necessary
upstream amplification (and the signal-to-noise ratio
deterioration) is directly proportional to the capacitance
value. The MAX4236/MAX4237 high-impedance, low-
Pin Description
PIN
SOT23 SO/µMAX
NAME FUNCTION
1 6 OUT Amplifier Output
24V
EE Negative Power Supply. Bypass with a 0.1µF capacitor to ground. Connect to GND
for single-supply operation.
3 3 IN+ Noninverting Amplifier Input
4 2 IN- Inverting Amplifier Input
58SHDN Shutdown Input. Do not leave floating. Connect to VCC for normal operation or GND
to enter the shutdown mode.
67V
CC Positive Supply Input. Bypass with a 0.1µF capacitor to ground.
—1, 5 N.C. No Connection. Not internally connected.
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
12 ______________________________________________________________________________________
current, low-noise inputs allow a minimum of capaci-
tance to be used.
Piezoresistive transducers applications require many of
the same qualities. For those applications the
MAX4236/MAX4237 high CMRR, PSRR, and offset sta-
bility are also a good match.
A typical application for a piezoresistive transducer
instrumentation amplifier design using the
MAX4236/MAX4237 is shown in the Typical Application
Circuit.
In general, the MAX4236/MAX4237 are good compo-
nents for any application in which an amplifier with an
almost zero input current is required, including high-
precision, long time-constant integrators and electro-
chemical sensors.
Power Supplies
The MAX4236/MAX4237 can operate from a single
+2.4V to +5.5V power supply, or from ±1.2V to ±2.75V
power supplies. The power supply pin(s) must be
bypassed to ground with a 0.1µF capacitor as close to
the pin as possible.
Layout and Physical Design
A good layout improves performance by decreasing
the amount of parasitic and stray capacitance, induc-
tance and resistance at the amplifier’s inputs, outputs,
and power-supply connections. Since parasitics might
be unavoidable, minimize trace lengths, resistor leads,
and place external components as close to the pins as
possible.
In high impedance, low input current applications, input
lines guarding and shielding, special grounding, and
other physical design and layout techniques, are
mandatory if good results are expected.
The negative effects of crosstalk, EMI and other forms
of interference and noise (thermal, acoustic, etc.) must
be accounted for and prevented beforehand for good
performance in the type of sensitive circuitry in which
the MAX4236/MAX4237 are likely to be used.
Selector Guide
PART GRADE MINIMUM
STABLE
GAIN TOP MARK
MAX4236EUT —1 AAUV
MAX4236AEUA A 1 —
MAX4236BEUA B 1 —
MAX4236AESA A 1 —
MAX4236BESA B 1 —
MAX4237EUT —5 AAUW
MAX4237AEUA A 5 —
MAX4237BEUA B 5 —
MAX4237AESA A 5 —
MAX4237BESA B 5 —
-VS
LOAD CELL
+VS
+VS
VOUT
-VS
MAX4236
MAX4236
Typical Application Circuit
Chip Information
TRANSISTOR COUNTS: 224
PROCESS: BiCMOS
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
______________________________________________________________________________________ 13
Package Information
6LSOT.EPS
8LUMAXD.EPS
MAX4236/MAX4237
SOT23, Very High Precision, 3V/5V
Rail-To-Rail Op Amps
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information (continued)
SOICN.EPS