MAX4091-MAX4092-MAX4094 Fast Delivery |IC PHOENIX CO.,LIMITED

MAX4091 ,Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op AmpsFeaturesThe single MAX4091, dual MAX4092, and quad♦ Low-Voltage, Single-Supply Operation (2.7V to 6 ..
MAX4091ASA ,Single/Dual/Quad / Micropower / Single-Supply / Rail-to-Rail Op AmpsApplicationsMAX4091AUK-T -40°C to +125°C 5 SOT23-5Portable Equipment MAX4091ASA -40°C to +125°C 8 S ..
MAX4091AUK+T ,Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op AmpsApplicationsMAX4091AUK-T -40°C to +125°C 5 SOT23-5Portable Equipment MAX4091ASA -40°C to +125°C 8 S ..
MAX4092 ,Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op AmpsApplicationsMAX4091AUK-T -40°C to +125°C 5 SOT23-5Portable Equipment MAX4091ASA -40°C to +125°C 8 S ..
MAX4092ASA ,Single/Dual/Quad / Micropower / Single-Supply / Rail-to-Rail Op AmpsELECTRICAL CHARACTERISTICS (continued)(V = 2.7V to 6V, V = GND, V = 0, V = V /2, T = +25°C.)CC EE C ..
MAX4092ASA+ ,Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op AmpsApplicationsMAX4091AUK-T -40°C to +125°C 5 SOT23-5Portable Equipment MAX4091ASA -40°C to +125°C 8 S ..
MAX776CSA ,-5V/-12V/-15V or Adjustable, High-Efficiency, Low IQ Inverting DC-DC ControllersMAX774/MAX775/MAX77619-0191; Rev 1; 3/94-5V/-12V/-15V or Adjustable, High-Efficiency, Low I Inverti ..
MAX776CSA ,-5V/-12V/-15V or Adjustable, High-Efficiency, Low IQ Inverting DC-DC ControllersGeneral Description ________
MAX776CSA ,-5V/-12V/-15V or Adjustable, High-Efficiency, Low IQ Inverting DC-DC ControllersApplicationsData Communicators__________Typical Operating Circuit __________________Pin Configurati ..
MAX776EPA ,-5V/-12V/-15V or Adjustable, High-Efficiency, Low IQ Inverting DC-DC ControllersELECTRICAL CHARACTERISTICS(V+ = 5V, I = 0mA, C = 0.1m F, T = T to T , unless otherwise noted. Typic ..
MAX776ESA ,-5V/-12V/-15V or Adjustable, High-Efficiency, Low IQ Inverting DC-DC ControllersApplicationsMAX774ESA -40°C to +85°C 8 SOMAX774MJA -55°C to +125°C 8 CERDIPLCD-Bias GeneratorsOrder ..
MAX777 ,(MAX778 / MAX779) Low Voltage Input Output / Setp up DC-DC ConvertersELECTRICAL CHARACTERISTICS MAX 777/MAX 7 78/MAX 7 79 (VIN = 2.5V, ILOAD = 0mA, LX Tr. 22pH, C ..

MAX4091-MAX4092-MAX4094
Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op Amps
General Description
The single MAX4091, dual MAX4092, and quad
MAX4094 operational amplifiers combine excellent DC
accuracy with Rail-to-Rail®operation at the input and
output. Since the common-mode voltage extends from
VCCto VEE, the devices can operate from either a sin-
gle supply (2.7V to 6V) or split supplies (±1.35V to
±3V). Each op amp requires less than 130µA of supply
current. Even with this low current, the op amps are
capable of driving a 1kΩload, and the input-referred
voltage noise is only 12nV/√Hz. In addition, these op
amps can drive loads in excess of 2000pF.
The precision performance of the MAX4091/MAX4092/
MAX4094 combined with their wide input and output
dynamic range, low-voltage, single-supply operation,
and very low supply current, make them an ideal
choice for battery-operated equipment, industrial, and
data acquisition and control applications. In addition,
the MAX4091 is available in space-saving 5-pin SOT23,
8-pin µMAX, and 8-pin SO packages. The MAX4092 is
available in 8-pin µMAX and SO packages, and the
MAX4094 is available in 14-pin TSSOP and 14-pin SO
packages.
________________________Applications
Portable Equipment
Battery-Powered Instruments
Data Acquisition and Control
Low-Voltage Signal Conditioning
FeaturesLow-Voltage, Single-Supply Operation (2.7V to 6V)Beyond-the-Rails™InputsNo Phase Reversal for Overdriven Inputs30µV Offset VoltageRail-to-Rail Output Swing with 1kΩLoadUnity-Gain Stable with 2000pF Load165µA (max) Quiescent Current Per Op Amp500kHz Gain-Bandwidth ProductHigh Voltage Gain (115dB)High Common-Mode Rejection Ratio (90dB) and
Power-Supply Rejection Ratio (100dB)Temperature Range (-40°C to +125°C)
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply
Rail-to-Rail Op Amps
VCC1OUT1
VCC
OUT2
IN2-
IN2+VEE
IN1+
IN1-
OUT1
μMAX/SO
TOP VIEW
N.C.
VCC
OUT
N.C.VEE
IN+
IN-
N.C.
μMAX/SOIN-3IN+VEE
SOT23
OUT4
IN4-
IN4+
VEEVCC
IN1+
IN1-
OUT1
IN3+
IN3-
OUT3OUT2
IN2-
IN2+
TSSOP/SO
MAX4091MAX4091MAX4092
MAX4094
Pin Configurations/Functional Diagrams
19-2272; Rev 0; 1/02
Ordering Information
PART TEMP RANGEPIN-PACKAGE
MAX4091AUK-T-40°C to +125°C5 SOT23-5
MAX4091ASA-40°C to +125°C8 SO
MAX4091AUA-40°C to +125°C8 µMAX
MAX4092ASA-40°C to +125°C8 SO
MAX4092AUA-40°C to +125°C8 µMAX
MAX4094AUD-40°C to +125°C14 TSSOP
MAX4094ASD-40°C to +125°C14 SO
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd.
Beyond-the-Rails is a trademark of Maxim Integrated Products, Inc.
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply,
Rail-to-Rail Op Amps
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= 2.7V to 6V, VEE= GND, VCM= 0, VOUT= VCC/2, TA= +25°C.)
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)....................................................7V
Common-Mode Input Voltage..........(VCC+ 0.3V) to (VEE- 0.3V)
Differential Input Voltage.........................................±(VCC- VEE)
Input Current (IN+, IN-)....................................................±10mA
Output Short-Circuit Duration
OUT shorted to GND or VCC.................................Continuous
Continuous Power Dissipation (TA= +70°C)
5-Pin SOT23 (derate 7.1mW/°C above +70°C)...........571mW
8-Pin SO (derate 5.88mW/°C above +70°C)...............471mW
8-Pin µMAX (derate 4.1mW/°C above +70°C)............330mW
14-Pin SO (derate 8.33mW/°C above +70°C).............667mW
14-Pin TSSOP (derate 9.1mW/°C above +70°C)........727mW
Operating Temperature Range.........................-40°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
DC CHARACTERISTICS
Supply Voltage RangeVCCInferred from PSRR test2.76.0V
VCC = 2.7V115165Supply CurrentICCVCM = VCC/2VCC = 5V130185µA
Input Offset VoltageVOSVCM = VEE to VCC0.031.4mV
Input Bias CurrentIBVCM = VEE to VCC20180nA
Input Offset CurrentIOSVCM = VEE to VCC0.27nA
Inp ut C om m on- M od e Rang eVCMInferred from CMRR testVEE - 0.05VCC + 0.05V
Common-Mode Rejection
RatioCMRR(VEE - 0.05V) ≤ VCM ≤ (VCC + 0.05V)7190dB
Power-Supply Rejection
RatioPSRR2.7V ≤ VCC ≤ 6V86100dB
Sourcing83105VCC = 2.7V, RL = 100kΩ
0.25V ≤ VOUT ≤ 2.45VSinking81105
Sourcing91105VCC = 2.7V, RL = 1kΩ
0.5V ≤ VOUT ≤ 2.2VSinking7890
Sourcing87115VCC = 5.0V, RL = 100kΩ
0.25V ≤ VOUT ≤ 4.75VSinking83115
Sourcing97110
Large-Signal Voltage Gain
(Note 1)AVOL
VCC = 5.0V, RL = 1kΩ
0.5V ≤ VOUT ≤ 4.5VSinking84100
RL = 100kΩ1569Output Voltage Swing High
(Note 1)VOH|VCC - VOUT|RL = 1kΩ130210mV
RL = 100kΩ1570Output Voltage Swing Low
(Note 1)VOL|VOUT - VEE|RL = 1kΩ80220mV
AC CHARACTERISTICS
Gain-Bandwidth ProductGBWPRL = 100kΩ, CL = 100pF500kHz
Phase MarginφMRL = 100kΩ, CL = 100pF60d eg r ees
Gain MarginRL = 100kΩ, CL = 100pF10dB
Slew RateSRRL = 100kΩ, CL = 15pF0.20V/µs
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply
Rail-to-Rail Op Amps
ELECTRICAL CHARACTERISTICS (continued)
(VCC= 2.7V to 6V, VEE= GND, VCM= 0, VOUT= VCC/2, TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Input-Noise Voltage DensityeNf = 10kHz12nV/√Hz
Input-Noise Current Densityf = 10kHz1.5pA/√Hz
Noise Voltage
(0.1Hz to 10Hz)16µVRMS
Total Harmonic Distortion
Plus NoiseTHD + Nf = 1kHz, RL = 10kΩ, CL = 15pF,
AV = 1, VOUT = 2VP-P0.003%
Capacitive-Load StabilityCLOADAV = 12000pF
Settling TimetSTo 0.1%, 2V step12µs
Power-On TimetONVCC = 0 to 3V step, VIN = VCC/2,
AV = 12µs
Op-Amp Isolationf = 1kHz (MAX4092/MAX4094)125dB
ELECTRICAL CHARACTERISTICS
(VCC= 2.7V to 6V, VEE= GND, VCM= 0, VOUT= VCC/2, TA= TMINto TMAX, unless otherwise noted. Typical values specified at = +25°C.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
DC CHARACTERISTICS
Supply Voltage RangeVCCInferred from PSRR test2.76.0V
VCC = 2.7V200Supply CurrentICCVCM = VCC/2VCC = 5V225µA
Input Offset VoltageVOSVCM = VEE to VCC±3.5mV
Input Offset Voltage TempcoΔVOS/ΔT±2µV/°C
Input Bias CurrentIBVCM = VEE to VCC±200nA
Input Offset CurrentIOSVCM = VEE to VCC±20nA
Input Common-Mode RangeVCMInferred from CMRR testV E E - 0.05 V C C + 0.05V
Common-Mode Rejection RatioCMRR(VEE - 0.05V) ≤ VCM ≤ (VCC + 0.05V)62dB
Power-Supply Rejection RatioPSRR2.7V ≤ VCC ≤ 6V80dB
Sourcing82VCC = 2.7V, RL = 100kΩ
0.25V ≤ VOUT ≤ 2.45VSinking80
Sourcing90VCC = 2.7V, RL = 1kΩ
0.5V ≤ VOUT ≤ 2.2VSinking76
Sourcing86VCC = 5V, RL = 100kΩ
0.25V ≤ VOUT ≤ 4.75VSinking82
Sourcing94
Large-Signal Voltage Gain
(Note 1)AVOL
VCC = 5V, RL = 1kΩ
0.5V ≤ VOUT ≤ 4.5VSinking80
RL = 100kΩ75Output Voltage Swing High
(Note 1)VOHVCC - VOUTRL = 1kΩ250mV
RL = 100kΩ75Output Voltage Swing Low
(Note 1)VOLVOUT - VEERL = 1kΩ250mV
Note 1:RLis connected to VEEfor AVOLsourcing and VOHtests. RLis connected to VCCfor AVOLsinking and VOLtests.
Note 2:All specifications are 100% tested at TA= +25°C. Specification limits over temperature (TA= TMINto TMAX) are guaranteed
by design, not production tested.
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply,
Rail-to-Rail Op Amps
0.011010,000
GAIN AND PHASE
vs. FREQUENCY
MAX4091 toc01
FREQUENCY (kHz)
GAIN (dB)
AV = 1000
NO LOAD
PHASE (DEGREES)
PHASE
GAIN
0.011010,000
GAIN AND PHASE
vs. FREQUENCY
MAX4091 toc02
FREQUENCY (kHz)
GAIN (dB)
CL = 470pF
AV = 1000
RL = ∞
PHASE (DEGREES)
GAIN
PHASE
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4091 toc03
FREQUENCY (kHz)
PSRR (dB)
VIN = 2.5V
VEE
VCC
0.011010,000
CHANNEL ISOLATION
vs. FREQUENCY
MAX4901 toc04
FREQUENCY (kHz)
CHANNEL SEPARATION (dB)
VIN = 2.5V
OFFSET VOLTAGE
vs. TEMPERATURE
MAX4091 toc05
TEMPERATURE (C)
OFFSET VOLTAGE (100
VCM = 0
OFFSET VOLTAGE vs.
COMMON-MODE VOLTAGE
MAX4091 toc06
COMMON-MODE VOLTAGE (V)
OFFSET VOLTAGE (534120
VCC = 2.7V
VCC = 6V
COMMON-MODE REJECTION RATIO
vs. TEMPERATURE
MAX4091 toc07
TEMPERATURE (C)
CMRR (dB)100
VCM = 0 TO 5V
VCM = -0.1V TO +5.1V
VCM = -0.2V TO +5.2V
VCM = -0.3V TO +5.3V
VCM = -0.4V TO +5.4V
INPUT BIAS CURRENT vs.
COMMON-MODE VOLTAGE
MAX4091 toc08
COMMON-MODE VOLTAGE (V)
INPUT BIAS CURRENT (nA)4321
VCC = 2.7V
VCC = 6V
INPUT BIAS CURRENT vs.
TEMPERATURE
MAX4091 toc09
TEMPERATURE (°C)
INPUT BIAS CURRENT (nA)
VCM = VCC
VCC = 2.7V
VCC = 6V
VCM = 0
VCC = 6V
Typical Operating Characteristics
(VCC= 5V, VEE= 0, TA= +25°C, unless otherwise noted.)
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply
Rail-to-Rail Op Amps
Typical Operating Characteristics (continued)
(VCC= 5V, VEE= 0, TA= +25°C, unless otherwise noted.)
SUPPLY CURRENT PER AMPLIFIER
vs. TEMPERATURE
MAX4091 toc10
TEMPERATURE (°C)
SUPPLY CURRENT PER AMP (
VOUT = VCM = VCC/2
VCC = 5V
VCC = 2.7V
SUPPLY CURRENT PER AMPLIFIER
vs. SUPPLY VOLTAGE
MAX4091 toc11
SUPPLY VOLTAGE (V)
SUPPLY CURRENT PER AMP (423
GAIN (dB)
MAX4091 toc12
VCC - VOUT (mV)
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
RL = 1kW
RL = 10kW
RL = 100kW
RL = 1MW
VCC = 6V
RL TO VEE
GAIN (dB)
MAX4091 toc13
VCC - VOUT (mV)
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
RL = 1kW
RL = 10kW
RL = 100kW
RL = 1MW
VCC = 2.7V
RL TO VEE
LARGE-SIGNAL GAIN
vs. TEMPERATURE
MAX4091 toc14
TEMPERATURE (C)
LARGE-SIGNAL GAIN (dB)100
RL TO VCC
RL TO VEE
RL = 1kW, 0.5V < VOUT < (VCC - 0.5V)
VCC = 2.7V
VCC = 6V
GAIN (dB)
MAX4091 toc15
VOUT (mV)
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
RL = 1MW
RL = 100kW
RL = 10kW
RL = 1kW
VCC = 6V
RL TO VCC
GAIN (dB)
MAX4091 toc16
VOUT (mV)
LARGE-SIGNAL GAIN
vs. OUTPUT VOLTAGE
RL = 1MW
RL = 100kW
RL = 10kW
RL = 1kW
VCC = 2.7V
RL TO VCC
LARGE-SIGNAL GAIN
vs. TEMPERATURE
MAX4091 toc17
TEMPERATURE (C)
LARGE-SIGNAL GAIN (dB)100
115RL TO VCC
RL TO VEE
RL = 100kW, 0.3V < VOUT < (VCC - 0.3V)
VCC = 2.7V
VCC = 6V
MINIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
MAX4091 toc18
TEMPERATURE (C)
RL TO VCC
VCC = 6V, RL = 1kW
VCC = 2.7V, RL = 1kW
VCC = 6V, RL = 100kW
VCC = 2.7V, RL = 100kW
MINIMUM V
OUT
(nV)
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply,
Rail-to-Rail Op Amps
MAXIMUM OUTPUT VOLTAGE
vs. TEMPERATURE
MAX4091 toc19
TEMPERATURE (C)
- V
OUT
) (mV)
RL TO VEE
VCC = 6V, RL = 1kW
VCC = 2.7V, RL = 1kW
VCC = 6V, RL = 100kW
VCC = 2.7V, RL = 100kW
0.011010,000
OUTPUT IMPEDANCE
vs. FREQUENCY
MAX40912 toc20
FREQUENCY (kHz)
OUTPUT IMPEDANCE (
0.111001,000
VCM = VOUT = 2.5V
VOLTAGE-NOISE DENSITY
vs. FREQUENCY
MAX4091 toc21
FREQUENCY (kHz)
VOLTAGE-NOISE DENSITY (nV/
Hz)
INPUT REFERRED
CURRENT-NOISE DENSITY
vs. FREQUENCY
MAX4091 toc22
FREQUENCY (kHz)
CURRENT-NOISE DENSITY (pA/
Hz)
INPUT REFERRED0.5
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. FREQUENCY
MAX4091 toc23
FREQUENCY (Hz)
THD + N (%)
10010,000
NO LOAD
RL = 10kW TO GND
AV = 1
2VP-P SIGNAL
80kHz LOWPASS FILTER
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. PEAK-TO-PEAK SIGNAL AMPLITUDE
MAX4091 toc24
PEAK-TO-PEAK SIGNAL AMPLITUDE (V)
THD + N (%)
RL = 10kW
RL = 100kW
AV = 1
1kHz SINE
22kHz FILTER
RL TO GNDRL = 1kW
RL = 2kW
VIN
50mV/div
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4091 toc25
2μs/div
VCC = 5V, AV = 1, RL = 10kΩ
VOUT
50mV/div
VIN
50mV/div
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4091 toc26
2μs/div
VOUT
50mV/div
VCC = 5V, AV = -1, RL = 10kΩ
VIN
2V/div
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4091 toc27
20μs/div
VOUT
2V/div
VCC = 5V, AV = 1, RL = 10kΩ
Typical Operating Characteristics (continued)
(VCC= 5V, VEE= 0, TA= +25°C, unless otherwise noted.)
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply
Rail-to-Rail Op Amps
Typical Operating Characteristics (continued)
(VCC= 5V, VEE= 0, TA= +25°C, unless otherwise noted.)
Pin Description
VIN
2V/div
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4091 toc28
20μs/div
VOUT
2V/div
VCC = 5V, AV = -1, RL = 10kΩ
SINK CURRENT vs.
OUTPUT VOLTAGE
MAX4091 toc29
OUTPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
VCC = 2.7V
VCC = 6V
VDIFF = 100mV
SOURCE CURRENT vs.
SUPPLY VOLTAGE
MAX4091 toc30
SUPPLY VOLTAGE (V)
OUTPUT CURRENT (mA)
VDIFF = 100mV
VCC = 2.7V
VCC = 6V
PIN
MAX4091MAX4091
SOT23SO/µMAXMAX4092MAX4094NAMEFUNCTION——OUTAmplifier Output
24411VEENegative Supply——IN+Noninverting Input——IN-Inverting Input
5784VCCPositive Supply1, 5, 8——N.C.No Connection. Not internally connected.11OUT1Amplifier 1 Output22IN1-Amplifier 1 Inverting Input33IN1+Amplifier 1 Noninverting Input55IN2+Amplifier 2 Noninverting Input66IN2-Amplifier 2 Inverting Input77OUT2Amplifier 2 Output
———8OUT3Amplifier 3 Output
———9IN3-Amplifier 3 Inverting Input
———10IN3+Amplifier 3 Noninverting Input
———12IN4+Amplifier 4 Noninverting Input
———13IN4-Amplifier 4 Inverting Input
———14OUT4Amplifier 4 Output
MAX4091/MAX4092/MAX4094
Single/Dual/Quad, Micropower, Single-Supply,
Rail-to-Rail Op Amps
Detailed Description
The single MAX4091, dual MAX4092 and quad
MAX4094op amps combine excellent DC accuracy
with rail-to-rail operation at both input and output. With
their precision performance, wide dynamic range at low
supply voltages, and very low supply current, these op
amps are ideal for battery-operated equipment, indus-
trial, and data acquisition and control applications.
Applications Information
Rail-to-Rail Inputs and Outputs
The MAX4091/MAX4092/MAX4094’s input common-
mode range extends 50mV beyond the positive and
negative supply rails, with excellent common-mode
rejection. Beyond the specified common-mode range,
the outputs are guaranteed not to undergo phase
reversal or latchup. Therefore, the MAX4091/MAX4092/
MAX4094 can be used in applications with common-
mode signals, at or even beyond the supplies, without
the problems associated with typical op amps.
The MAX4091/MAX4092/MAX4094’s output voltage
swings to within 15mV of the supplies with a 100kΩ
load. This rail-to-rail swing at the input and the output
substantially increases the dynamic range, especially
in low-supply-voltage applications. Figure 1 shows the
input and output waveforms for the MAX4092, config-
ured as a unity-gain noninverting buffer operating from
a single 3V supply. The input signal is 3.0VP-P, a 1kHz
sinusoid centered at 1.5V. The output amplitude is
approximately 2.98VP-P.
Input Offset Voltage
Rail-to-rail common-mode swing at the input is obtained
by two complementary input stages in parallel, which
feed a folded cascaded stage. The PNP stage is active
for input voltages close to the negative rail, and the NPN
stage is active for input voltages close to the positive rail.
The offsets of the two pairs are trimmed. However,
there is some residual mismatch between them. This
mismatch results in a two-level input offset characteris-
tic, with a transition region between the levels occurring
at a common-mode voltage of approximately 1.3V
above VEE. Unlike other rail-to-rail op amps, the transi-
tion region has been widened to approximately 600mV
in order to minimize the slight degradation in CMRR
caused by this mismatch.
The input bias currents of the MAX4091/MAX4092/
MAX4094 are typically less than 20nA. The bias current
flows into the device when the NPN input stage is
active, and it flows out when the PNP input stage is
active. To reduce the offset error caused by input bias
current flowing through external source resistances,
match the effective resistance seen at each input.
Connect resistor R3 between the noninverting input and
ground when using the op amp in an inverting configu-
ration (Figure 2a); connect resistor R3 between the
noninverting input and the input signal when using the
op amp in a noninverting configuration (Figure 2b).
Select R3 to equal the parallel combination of R1 and
R2. High source resistances will degrade noise perfor-
mance, due to the the input current noise (which is mul-
tiplied by the source resistance).
Input Stage Protection Circuitry
The MAX4091/MAX4092/MAX4094 include internal pro-
tection circuitry that prevents damage to the precision
input stage from large differential input voltages. This
protection circuitry consists of back-to-back diodes
between IN+ and IN- with two 1.7kΩresistors in series
(Figure 3). The diodes limit the differential voltage
applied to the amplifiers’ internal circuitry to no more
than VF, where VFis the diodes’ forward-voltage drop
(about 0.7V at +25°C).
Input bias current for the ICs (±20nA) is specified for
small differential input voltages. For large differential
input voltages (exceeding VF), this protection circuitry
increases the input current at IN+ and IN-:
Output Loading and Stability
Even with their low quiescent current of less than
130µA per op amp, the MAX4091/MAX4092/MAX4094
are well suited for driving loads up to 1kΩwhile main-
taining DC accuracy. Stability while driving heavy
capacitive loads is another key advantage over compa-
rable CMOS rail-to-rail op amps.
In op amp circuits, driving large capacitive loads
increases the likelihood of oscillation. This is especially
true for circuits with high-loop gains, such as a unity-
gain voltage follower. The output impedance and a
capacitive load form an RC network that adds a pole to
the loop response and induces phase lag. If the pole
frequency is low enough—as when driving a large
capacitive load––the circuit phase margin is degraded,
leading to either an under-damped pulse response or
oscillation.
The MAX4091/MAX4092/MAX4094 can drive capacitive
loads in excess of 2000pF under certain conditions
(Figure 4). When driving capacitive loads, the greatest
potential for instability occurs when the op amp is
sourcing approximately 200µA. Even in this case, sta-
bility is maintained with up to 400pF of output capaci-
INPUTCURRENTVVVINF=−−+− [() ()] .217✕Ω

Partno	Mfg	Dc	Qty	Available	Descript
MAX4091	MAXIM	N/a	500	avai	Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op Amps
MAX4092	MAXIM	N/a	500	avai	Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op Amps
MAX4094	MAXIM	N/a	500	avai	Single/Dual/Quad, Micropower, Single-Supply, Rail-to-Rail Op Amps