MAX4292EBL+T ,Ultra-Small, +1.8V, µPower, Rail-to-Rail I/O Op AmpsMAX4291/MAX4292/MAX429419-1612; Rev 3; 4/02Ultra-Small, 1.8V, µPower,Rail-to-Rail I/O Op Amps
MAX4292ESA ,Dual, ultra-small, single supply +1.8V to +5.5V or dual supples +-0.9V to +-2.75V, micropower, Rail-to-Rail I/O op amp.ELECTRICAL CHARACTERISTICS(V = +1.8V to +5.5V, V = V = 0, V = V / 2, R = 100kΩ connected to V / 2, ..
MAX4292EUA ,Dual, ultra-small, single supply +1.8V to +5.5V or dual supples +-0.9V to +-2.75V, micropower, Rail-to-Rail I/O op amp.applications.The MAX4291/MAX4292/MAX4294 have an input com- Rail-to-Rail Output Drives 2kΩ Loadmo ..
MAX4292EUA ,Dual, ultra-small, single supply +1.8V to +5.5V or dual supples +-0.9V to +-2.75V, micropower, Rail-to-Rail I/O op amp.ELECTRICAL CHARACTERISTICS(V = +1.8V to +5.5V, V = V = 0, V = V / 2, R = 100kΩ connected to V / 2, ..
MAX4292EUA ,Dual, ultra-small, single supply +1.8V to +5.5V or dual supples +-0.9V to +-2.75V, micropower, Rail-to-Rail I/O op amp.ApplicationsOrdering Information2-Cell Battery-Operated Systems PIN- TOPPART TEMP. RANGEPACKAGE MAR ..
MAX4292EUA-T ,Ultra-Small, +1.8V, µPower, Rail-to-Rail I/O Op AmpsApplications PIN- TOP 2-Cell Battery-Operated Systems PART TEMP RANGE PACKAGE MARKPortable Electron ..
MAX811SEUS-T ,Microprocessor voltage monitor with manual reset input. Reset threshold voltage 2.93VFeaturesThe MAX811/MAX812 are low-power microprocessor Precision Monitoring of 3V, 3.3V, and 5V (µ ..
MAX811TEUS ,PLASTIC ENCAPSULATED DEVICES MAX811TEUS Rev. A RELIABILITY REPORT FOR MAX811TEUS PLASTIC ENCA ..
MAX811TEUS ,PLASTIC ENCAPSULATED DEVICES MAX811TEUS Rev. A RELIABILITY REPORT FOR MAX811TEUS PLASTIC ENCA ..
MAX811TEUS+ ,4-Pin µP Voltage Monitors with Manual Reset InputElectrical Characteristics(V = 5V for L/M versions, V = 3.3V for T/S versions, V = 3V for R version ..
MAX811TEUS+T ,4-Pin µP Voltage Monitors with Manual Reset InputFeaturesThe MAX811/MAX812 are low-power microprocessor• Integrated Voltage Monitor Increases System ..
MAX811TEUS-T ,Microprocessor voltage monitor with manual reset input. Reset threshold voltage 3.08VMAX811/MAX81219-0411; Rev 3; 3/994-Pin µP Voltage Monitors with Manual Reset Input________________
MAX4291EUK+T-MAX4291EXK+T-MAX4292EBL+T-MAX4292EUA-T-MAX4294ESD+T-MAX4294EUD+
Ultra-Small, +1.8V, µPower, Rail-to-Rail I/O Op Amps
General DescriptionThe MAX4291/MAX4292/MAX4294 family of micropow-
er operational amplifiers operates from a 1.8V to 5.5V
single supply or ±0.9V to ±2.75V dual supplies and has
Rail-to-Rail®input/output capabilities. These amplifiers
provide a 500kHz gain-bandwidth product and 120dB
open-loop voltage gain while using only 100µA of sup-
ply current per amplifier. The combination of low input
offset voltage (±200µV) and high open-loop gain makes
them ideal for low-power/low-voltage, high-precision
portable applications.
The MAX4291/MAX4292/MAX4294 have an input com-
mon-mode range that extends to each supply rail, and
their outputs swing to within 46mV of the rails with a 2kΩ
load. Although the minimum operating voltage is speci-
fied at 1.8V, these devices typically operate down to
1.5V. The combination of ultra-low-voltage operation, rail-
to-rail inputs/output, and low-power consumption makes
these devices ideal for any portable/two-cell battery-pow-
ered system.
The single MAX4291 is offered in an ultra-small 5-pin
SC70 package. The dual MAX4292 is offered in a
space-saving 8-bump, 1.5mm X 1.5mm footprint, ultra
chip-scale package (UCSP™).
Applications2-Cell Battery-Operated Systems
Portable Electronic Equipment
Battery-Powered Instrumentation
Digital Scales
Strain Gauges
Sensor Amplifiers
Cellular Phones
FeaturesUltra-Low Voltage Operation—Guaranteed Down
to 1.8V100µA Supply Current per Amplifier500kHz Gain-Bandwidth Product120dB Open-Loop Voltage Gain (RL= 100kΩ)0.017% Total Harmonic Distortion Plus Noise
(THD + N) at 1kHzRail-to-Rail Input Common-Mode RangeRail-to-Rail Output Drives 2kΩLoadNo Phase Reversal for Overdriven InputsUnity-Gain Stable for Capacitive Loads up to 100pF200µV Input Offset Voltage (MAX4292/MAX4294)Single in Small 5-Pin SC70Available in Ultra-Small Packages:
5-Pin SC70 (MAX4291)
8-Bump UCSP (MAX4292)
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps19-1612; Rev 3; 4/02
Pin ConfigurationsRail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
UCSP is a trademark of Maxim Integrated Products, Inc.
Ordering Information
Selector GuidePART AMPLIFIERS PIN-PACKAGEMAX4291 1 5-pin SC70/SOT23MAX4292 2 8-pin µMAX/SO/UCSPMAX4294 4 14-pin SO/TSSOP
TOP VIEW
(BUMPS ON BOTTOM)
OUTAVCCOUTB
INA-
INA+
INB-
INB+VEE
UCSPMAX4292
Pin Configurations continued at end of data sheet.
*UCSP reliability is integrally linked to the user’s assembly
methods, circuit board material, and environment. Refer to the
UCSP Reliability Notice in the UCSP Reliability section of this
data sheet for more information.
PART TEMP RANGE PIN-
PACKAGE TOP
MARKMAX4291EXK-T -40°C to +85°C 5 SC70-5 AADMAX4291EUK-T -40°C to +85°C 5 SOT23-5 ADML
MAX4292EBL-T* -40°C to +85°C 8 UCSP-8 AAJMAX4292EUA -40°C to +85°C 8 µMAX —MAX4292ESA -40°C to +85°C 8 SO —
MAX4294ESD -40°C to +85°C 14 SO —MAX4294EUD -40°C to +85°C 14 TSSOP —
Common-Mode Rejection Ratio
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= 1.8V to 5.5V, VEE= VCM= 0, VOUT= VCC/2, RL= 100kΩconnected to VCC/2, TA
= +25°C, unless otherwise noted.)(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 (VCCto VEE)....................................................6V
All Other Pins...................................(VCC+ 0.3V) to (VEE- 0.3V)
Current into IN_+, IN_-.....................................................±25mA
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (TA= +70°C)
5-Pin SC70 (derate 2.5mW/°C above +70°C)................200mW
5-Pin SOT23 (derate 7.1mW/°C above +70°C)................571mW
8-Bump UCSP (derate 4.7mW/°C above +70°C)...........379mW
8-Pin µMAX (derate 4.10mW/°C above +70°C)..............330mW
8-Pin SO (derate 5.88mW/°C above +70°C)..................471mW
14-Pin SO (derate 8.33mW/°C above +70°C)................667mW
14-Pin TSSOP (derate 6.3mW/°C above +70°C)............500mW
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
MAX4292/MAX4294±200±1200
VCC= 5.0V, 0 ≤VCM≤5.0VnA±15±60IBInput Bias Current
VCC= 1.8V
Inferred from PSRR test
Inferred from CMRR test
|VIN+- VIN-| < 10mV
VCC= 5.0V, 0 ≤VCM≤5.0V
MAX4291
CONDITIONS100210IQ1.85.5VCCSupply Voltage Range
Quiescent Supply Current
(Per Amplifier)0VCCVCMInput Common-Mode Voltage
Range0.75RINDifferential Input Resistance±1±7IOSInput Offset Current ±400±2500VOSInput Offset Voltage
UNITSMINTYPMAXSYMBOLPARAMETERVCC= 5.0V100255100dBPSRRPower-Supply Rejection Ratio80
Tested for
0 ≤VCM≤
1.8V;
VCC= 1.8V
CMRRCommon-Mode Rejection Ratio8090
Tested for
0 ≤VCM≤
5.0V,
VCC= 5.0V
MAX4291
MAX4292/MAX4294
MAX4291
MAX4292/MAX42946690
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
ELECTRICAL CHARACTERISTICS(VCC= 1.8V to 5.5V, VEE= VCM= 0, VOUT= VCC/2, RL= 100kΩconnected to VCC/2, TA
= TMINto TMAX, unless otherwise noted.)(Note 1)
ELECTRICAL CHARACTERISTICS (continued)(VCC= 1.8V to 5.5V, VEE= VCM= 0, VOUT= VCC/2, RL= 100kΩconnected to VCC/2, TA
= +25°C, unless otherwise noted.)(Note 1)
Channel-to-Channel Isolation
Gain-Bandwidth Product
Phase Margin
Gain Margin
Slew Rate
Input Voltage-Noise Density
Input Current-Noise Density
Capacitive-Load Stability
CHISO
GBWP
Specified at f = 10kHz (MAX4292/MAX4294 only)
f = 10kHz
f = 10kHz
AVCL= 1V/V,no sustained oscillations
100pF
pA/√Hz
nV/√Hz
V/µs
degrees
kHz20Sourcing or sinkingIOUT(SC)Output Short-Circuit Current
Output-Voltage Swing LowVOLSpecified as
|VEE- VOL|RL= 2kΩto VCC/2= 100kΩto VCC/212080mV1540
220= 2kΩto VCC/2= 100kΩto VCC/2Specified as
|VCC- VOH|VOHOutput-Voltage Swing High
Large-Signal Voltage GainAV
VCC= 5.0V
VCC= 1.8V= 100kΩ,
0.02V ≤VOUT≤VCC- 0.02V= 2kΩ,
0.1V ≤VOUT≤VCC- 0.1V= 100kΩ,
0.02V ≤VOUT≤VCC- 0.02V= 2kΩ,
0.1V ≤VOUT≤VCC- 0.1V80120130110120
UNITSMINTYPMAXCONDITIONSSYMBOLPARAMETER270VCC= 5.0V
PARAMETERSYMBOLMINTYPMAXUNITS±2000Input Offset VoltageVOS±3000µV
Quiescent Supply Current
(Per Amplifier)
Supply-Voltage RangeVCC1.85.5V240µA
CONDITIONSMAX4292/MAX4294
MAX4291
Inferred from PSRR test
VCC= 1.8V
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
Note 1:All devices are 100% tested at TA= +25°C. All temperature limits are guaranteed by design.
ELECTRICAL CHARACTERISTICS (continued)(VCC= 1.8V to 5.5V, VEE= VCM= 0, VOUT= VCC/2, RL= 100kΩconnected to VCC/2, TA
= TMINto TMAX, unless otherwise noted.)(Note 1)
MAX4291/MAX4292/MAX4294120RL= 2kΩto VCC/2= 100kΩto VCC/2= 100kΩto VCC/2
VCC= 5.0V= 2kΩ,
0.1V ≤VOUT≤VCC- 0.1V= 100kΩ,
0.02V ≤VOUT≤VCC- 0.02V= 2kΩ,
0.1V ≤VOUT≤VCC- 0.1V= 100kΩ,
0.02V ≤VOUT≤VCC- 0.02V
PARAMETERSYMBOLMINTYPMAXUNITSLarge-Signal Voltage GainAV
Input Common-Mode Voltage
RangeVCM0VCCV
Output-Voltage Swing HighVOH20mV
Output-Voltage Swing LowVOLmV
Input Bias Current
Input Offset Voltage DriftTCVOS1.2µV/°C±90nA
Input Offset CurrentIOS±10nA
CONDITIONSVCC= 1.8V
Inferred from CMRR test
Specified as
|VCC- VOH|
Specified as
|VEE- VOL|
VCC= 5.0V, 0 ≤VCM≤5.0V
VCC= 5.0V, 0 ≤VCM≤5.0V
CMRRCommon-Mode Rejection Ratio
Tested for
0 ≤VCM≤1.8V,
VCC= 1.8VdBPSRRPower-Supply Rejection Ratio
Tested for
0 ≤VCM≤5.0V,
VCC= 5.0V
MAX4291
MAX4292/MAX4294
MAX4291
MAX4292/MAX4294RL= 2kΩto VCC/2
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
MAX4291/MAX4292/MAX4294MINIMUM OPERATING VOLTAGE
vs. TEMPERATURE (PSRR ≥ 80dB)
MAX4291 toc02
TEMPERATURE (°C)
MINIMUM OPERATING VOLTAGE (V)
INPUT OFFSET VOLTAGE
vs. TEMPERATURE
MAX4291 toc03
TEMPERATURE (°C)
INPUT OFFSET VOLTAGE (VCC = 5.5V
VCC = 1.8V
VCC = 2.4V
INPUT BIAS CURRENT
vs. TEMPERATURE
MAX4291 toc04
TEMPERATURE (°C)
INPUT BIAS CURRENT (nA)
VCC = 5.5V
VCC = 1.8V
INPUT BIAS CURRENT vs.
COMMON-MODE VOLTAGE (VCC = 1.8V)
MAX4291 toc05
COMMON-MODE VOLTAGE (V)
INPUT BIAS CURRENT (nA)
INPUT BIAS CURRENT vs.
COMMON-MODE VOLTAGE (VCC = 5.5V)
MAX4291 toc06
COMMON-MODE VOLTAGE (V)
INPUT BIAS CURRENT (nA)
OUTPUT VOLTAGE SWING vs.
TEMPERATURE (RL = 100kΩ TO VCC/2)
MAX4291-07
TEMPERATURE (°C)
OUTPUT VOLTAGE SWING (mV)
VOH = VCC - VOUT
VOL = VOUT - VEE
VOH (VCC = 5.5V OR 1.8V)
VOL (VCC = 5.5V)
VOL (VCC = 1.8V)
OUTPUT VOLTAGE SWING vs.
TEMPERATURE (RL = 2kΩ TO VCC/2)
MAX4291-08
TEMPERATURE (°C)
OUTPUT VOLTAGE SWING (mV)
VOH = VCC - VOUT
VOL = VOUT - VEE
VOH (VCC = 1.8V)
VOL (VCC = 5.5V)
VOL (VCC = 1.8V)
VOH (VCC = 5.5V)
COMMON-MODE REJECTION RATIO
vs. TEMPERATURE
MAX4291 toc09
TEMPERATURE (°C)
CMRR (dB)
VCC = 5.5V
VCC = 1.8V
0 ≤ VCM ≤ VCC
Typical Operating Characteristics(VCC= 2.4V, VEE= VCM= 0, VOUT= VCC/2, no load, TA= +25°C, unless otherwise noted.)
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
MAX4291 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (
VCC = 5.5V
VCC = 1.8V
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
Typical Operating Characteristics (continued)(VCC= 2.4V, VEE= VCM= 0, VOUT= VCC/2, no load, TA= +25°C, unless otherwise noted.)
OPEN-LOOP GAIN vs. OUTPUT SWING LOW
(VCC = 1.8V, RL CONNECTED TO VCC)
MAX4291 toc10
VOL (mV)
GAIN (dB)
RL = 2kΩ
RL = 1kΩ
OPEN-LOOP GAIN vs. OUTPUT SWING HIGH
(VCC = 1.8V, RL CONNECTED TO VEE)
MAX4291 toc11
VOH (mV)
GAIN (dB)
RL = 2kΩ
RL = 1kΩ
OPEN-LOOP GAIN vs. OUTPUT SWING LOW
(VCC = 5.5V, RL CONNECTED TO VCC)
MAX4191 toc12
VOL (mV)
GAIN (dB)
RL = 2kΩ
RL = 1kΩ
OPEN-LOOP GAIN vs. OUTPUT SWING HIGH
(VCC = 5.5V, RL CONNECTED TO VEE)
MAX4191 toc13
VOH (mV)
GAIN (dB)
RL = 2kΩ
RL = 1kΩ
OPEN-LOOP GAIN vs. TEMPERATURE
MAX4291 toc14
TEMPERATURE (°C)
OPEN-LOOP GAIN (dB)
RL = 2kΩ TO VCC
RL = 2kΩ TO VEERL = 1kΩ TO VCC
RL = 1kΩ TO VEE
VCC = 5.5V
GAIN AND PHASE vs. FREQUENCY
(CL = 100pF)
MAX4291 toc17
FREQUENCY (kHz)
GAIN (dB)0
AV = 1000V/V180
PHASE (DEGREES)
FREQUENCY (kHz)
THD + NOISE (%)0.1
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCYVCC = 5.5V
VCC = 1.8V
MAX4291 toc18
RL = 2kΩ
Av = 1V/V
(NONINVERTING
CONFIGURATION)
MAX4292/MAX4294
CROSSTALK vs. FREQUENCY
MAX4291-15
FREQUENCY (kHz)
CROSSTALK (dB)
GAIN AND PHASE vs. FREQUENCY
(CL = 0)
MAX4291 toc16
FREQUENCY (kHz)
GAIN (dB)0
AV = 1000V/V180
PHASE (DEGREES)
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op AmpsLOAD RESISTOR vs. CAPACITIVE LOAD
MAX4291 toc19
CAPACITIVE LOAD (nF)
LOAD RESISTOR (k
IOUT > 20mA
VCC = 2.4V
IOUT > 20mA
VCC = 5.5V
VCC = 5.5V
VCC = 2.4V
10% OVERSHOOT
AV = 1V/V
(NONINVERTING CONFIGURATION)
OUT
100mV
100mV
1μs/div
SMALL-SIGNAL TRANSIENT RESPONSE
(NONINVERTING CONFIGURATION)MAX4291 toc20
VCC = 2.5V
VEE = -2.5V
VCM = 0
OUT
100mV
100mV
1μs/div
SMALL-SIGNAL TRANSIENT RESPONSE
(INVERTING CONFIGURATION)MAX4291 toc21
VCC = 2.5V
VEE = -2.5V
VCM = 0
OUT
-2V
-2V
10μs/div
LARGE-SIGNAL TRANSIENT RESPONSE
(NONINVERTING CONFIGURATION)MAX4291 toc22
VCC = 2.5V
VEE = -2.5V
VCM = 0
OUT
-2V
-2V
10μs/div
LARGE-SIGNAL TRANSIENT RESPONSE
(INVERTING CONFIGURATION)MAX4291 toc23
VCC = 2.5V
VEE = -2.5V
VCM = 0
SUPPLY CURRENT vs. SINK CURRENT
MAX4291/2/4-24
SINK CURRENT (mA)
SUPPLY CURRENT (
VCC = 5.5V
VCC = 2.4V
VCC = 1.8V
SUPPLY CURRENT vs. SOURCE CURRENT
MAX4291/2/4-25
SOURCE CURRENT (mA)
SUPPLY CURRENT (VCC = 5.5V
VCC = 1.8V
VCC = 2.4V
Typical Operating Characteristics (continued)(VCC= 2.4V, VEE= VCM= 0, VOUT= VCC/2, no load, TA= +25°C, unless otherwise noted.)
Detailed Description
Rail-to-Rail Input StageThe MAX4291/MAX4292/MAX4294 have rail-to-rail
inputs and output stages that are specifically designed
for low-voltage, single-supply operation in the smallest
package possible. The input stage consists of separate
NPN and PNP differential stages, which operate togeth-
er to provide a common-mode range extending to both
supply rails. The crossover region of these two pairs
occurs halfway between VCCand VEE. The input offset
voltage is typically ±200µV (MAX4292/MAX4294). Low
operating supply voltage, low supply current, rail-to-rail
common-mode input range, and rail-to-rail outputs
make this family of operational amplifiers (op amps) an
excellent choice for precision or general-purpose, low-
voltage, battery-powered systems.
Since the input stage consists of NPN and PNP pairs,
the input bias current changes polarity as the common-
mode voltage passes through the crossover region.
Match the effective impedance seen by each input to
reduce the offset error caused by input bias currents
flowing through external source impedances (Figures
1a and 1b).
The combination of high-source impedance plus input
capacitance (amplifier input capacitance plus stray
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
Pin DescriptionR3 = R1 R2R2
MAX4291
MAX4292
MAX4294
R3 = R1 R2R2
MAX4291
MAX4292
MAX4294
Figure 1a. Minimizing Offset Error Due to Input Bias Current
(Noninverting)
Figure 1b. Minimizing Offset Error Due to Input Bias Current
(Inverting)
PIN
MAX4292MAX4291µMAX/SOUCSPMAX4294NAMEFUNCTION———IN+Noninverting Input4C211VEENegative Supply. Connect to ground for
single-supply operation.———IN-Inverting Input———OUTAmplifier Output8A24VCCPositive Supply1, 7A1, A31, 7OUTA, OUTBOutputs for Amplifiers A and B2, 6B1, B32, 6INA-, INB-Inverting Inputs to Amplifiers A and B3, 5C1, C33, 5INA+, INB+Noninverting Inputs to Amplifiers A and B—8, 14OUTC, OUTDOutputs for Amplifiers C and D—9, 13INC-, IND-Inverting Inputs to Amplifiers C and D—10, 12INC+, IND+Noninverting Inputs to Amplifiers C and D
capacitance) creates a parasitic pole that produces an
underdamped signal response. Reducing input capaci-
tance or placing a small capacitor across the feedback
resistor improves response in this case.
The MAX4291/MAX4292/MAX4294 family’s inputs are
protected from large differential input voltages by inter-
nal 10.6kΩseries resistors and back-to-back triple-
diode stacks across the inputs (Figure 2). For
differential input voltages (much less than 1.8V), input
resistance is typically 0.75MΩ. For differential input
voltages greater than 1.8V, input resistance is around
21.2kΩ, and the input bias current can be approximat-
ed by the following equation:
In the region where the differential input voltage
approaches 1.8V, the input resistance decreases expo-
nentially from 0.75MΩto 21.2kΩas the diode block
begins to conduct. Conversely, the bias current
increases with the same curve.
In unity-gain configuration, high slew-rate input signals
may capacitively couple to the output through the triple-
diode stacks.
Rail-to-Rail Output StageThe MAX4291/MAX4292/MAX4294 output stage can
drive up to a 2kΩload and still swing to within 46mV of
the rails. Figure 3 shows the output-voltage swing of a
MAX4291 configured as a unity-gain buffer, powered
from a ±2.5V supply. The output for this setup typically
swings from (VEE+ 25mV) to (VCC- 2mV) with a 100kΩ
load.
Applications Information
Power-Supply ConsiderationsThe MAX4291/MAX4292/MAX4294 operate from a sin-
gle 1.8V to 5.5V supply (or dual ±0.9V to ±2.75V sup-
plies) and consume only 100µA of supply current per
amplifier. A high power-supply rejection ratio of 100dB
allows the amplifiers to be powered directly off a
decaying battery voltage, simplifying design and
extending battery life.
The MAX4291/MAX4292/MAX4294 are ideally suited for
use with most battery-powered systems. Table 1 lists a(V-1.8V)
21.2kBIASDIFF=Ω
MAX4291/MAX4292/MAX4294
Ultra-Small, 1.8V, µPower,
Rail-to-Rail I/O Op Amps
Table 1. MAX4291 Characteristics with Typical Battery Systems750YesNickel-Cadmium
(2 cells)
1000YesLithium-Ion
(1 cell)
1000YesNickel-Metal-
Hydride (2 cells)
2000NoAlkaline (2 cells)
BATTERY TYPECAPACITY, AA SIZE
(mA-h)VEND-OF-LIFE(V)VFRESH
(V)
RECHARGE-
ABLE
10,000
10,000
20,000
MAX4291
OPERATING TIME IN
NORMAL MODE
(h)OUT
2.5V/div
2.5V/div
20μs/div
VCC = 2.5V, VEE = -2.5V
Figure 3. Rail-to-Rail Input/Output Voltage Range
10.6kΩ
10.6kΩ
IN-
IN+
Figure 2. Input Protection Circuit
