MAX4037EUT Fast Delivery |IC PHOENIX CO.,LIMITED

MAX4037EUT ,Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps with +1.2V Buffered ReferenceApplicationsPIN- TOPBattery-Powered/Solar-Powered SystemsPART TEMP RANGEPACKAGE MARKPortable Medica ..
MAX4039EUB ,Low IBIAS / +1.4V/800nA / Rail-to-Rail Op Amps with +1.2V Buffered ReferenceApplications PACKAGE MARKMAX4036EXK-T -40°C to +85°C 5 SC70-5 AFRBattery-Powered/Solar-Powered Syst ..
MAX4040ESA ,Single/Dual/Quad / Low-Cost / SOT23 / Micropower Rail-to-Rail I/O Op AmpsApplicationsMAX4041ESA -40°C to +85°C 8 SO —Battery-Powered Strain GaugesMAX4041EUA -40°C to +85°C ..
MAX4040ESA+ ,Single/Dual/Quad, Low-Cost, SOT23, Micropower Rail-to-Rail I/O Op AmpsApplicationsMAX4041ESA -40°C to +85°C 8 SO —Battery-Powered Strain GaugesMAX4041EUA -40°C to +85°C ..
MAX4040EUA ,Single/Dual/Quad / Low-Cost / SOT23 / Micropower Rail-to-Rail I/O Op AmpsELECTRICAL CHARACTERISTICS—T = +25°CA(V = +5.0V, V = 0, V = 0, V = V / 2, SHDN = V , R = 100kΩ tied ..
MAX4040EUK ,Single/Dual/Quad, Low-Cost, SOT23, Micropower Rail-to-Rail I/O Op Ampsapplications.Ordering InformationThe MAX4040 is offered in a space-saving 5-pin SOT23PIN- SOT packa ..
MAX7545AKCWP ,CMOS 12-BIT BUFFERED MULTIPLYING DACsApplications Motion Control Systems Automatic Test Equipment pp Controlled Systems Progra ..
MAX7545ALP ,CMOS 12-BIT BUFFERED MULTIPLYING DACsfeatures a 100ns max write pulse width (150ns for MAX7645) which allows inter- facing to a wide r ..
MAX754CPE ,CCFL Backlight and LCD Contrast ControllersMAX753/MAX75419-0197; Rev 1; 1/95CCFL Backlight andLCD Contrast Controllers_______________
MAX754CSE ,CCFL Backlight and LCD Contrast ControllersBlock Diagram located at end of data sheet.____ Maxim Integrated Products 1 for or literature.CCF ..
MAX754ESE ,CCFL Backlight and LCD Contrast ControllersGeneral Description ________
MAX755CPA ,-5V/Adjustable, Negative-Output,Inverting, Current-mode PWM RegulatorsApplications Board-Level DC-DC Conversion Battery-Powered Equipment Computer Peripherals Ty ..

MAX4037EUT
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps with +1.2V Buffered Reference
General Description
The single MAX4036/MAX4037 and dual MAX4038/
MAX4039 operational amplifiers operate from a single
+1.4V to +3.6V (without reference) or +1.8V to +3.6V (with
reference) supply and consume only 800nA of supply
current per amplifier, and 1.1µA for the optional refer-
ence. The MAX4036/MAX4038 feature a common-mode
input voltage range from 0V to VDD- 0.4V at VDD= 1.4V.
The MAX4037/MAX4039 feature a 1.232V voltage refer-
ence capable of sourcing 100µA and sinking 20µA.
The MAX4036–MAX4039s’ rail-to-rail outputs drive 5kΩ
loads to within 25mV of the rails. Ultra-low supply current,
low operating voltage, and rail-to-rail outputs make the
MAX4036–MAX4039 ideal for use in single-cell lithium-ion
(Li+), or two-cell NiCd/NiMH/alkaline battery-powered
applications.
The MAX4036 is available in an SC70 package, the
MAX4037 in a SOT23 package, and the MAX4038/
MAX4039 in UCSP™, µMAX®, and TDFN packages.
Applications
Battery-Powered/Solar-Powered Systems
Portable Medical Instrumentation
Pagers and Cell Phones
Micropower Thermostats and Potentiostats
Electrometer Amplifiers
Remote Sensor Amplifiers
Active Badges
pH Meters
FeaturesUltra-Low 800nA per Amplifier Supply CurrentUltra-Low 1.4V Supply Voltage Operation (1.8V for
MAX4037/MAX4039)Rail-to-Rail Outputs Drive 5kΩand 5000pF Load1.232V ±0.5%, 120ppm/°C (max) Reference
(MAX4037/MAX4039)No External Reference Bypass Capacitor
RequiredNo Phase Reversal for Overdriven InputsLow 1.0pA (typ) Input Bias CurrentLow 200µV Input Offset VoltageUnity-Gain StableAvailable in Tiny UCSP, SC70, SOT23, TDFN, and
µMAX PackagesAvailable in -40°C to +125°C Temperature Range
(MAX4036A/MAX4038A)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
INA+SENSOR
REF
INB+
OUTA
INB-
OUTB
INA-
VDD
VSS
MAX4039
ADC
Typical Operating Circuit
Ordering Information
MAX4039OUTA
REF
INA-
INA+
VSS
OUTB
INB-
INB+
VDD
REF
Functional Diagram
19-3142; Rev 5; 11/09
+Denotes a lead(Pb)-free/RoHS-compliant package.
-Denotes a package containing lead.
*EP = Exposed pad.
Ordering Information continued at end of data sheet.µMAX is a registered trademark and UCSP is a trademark of
Maxim Integrated Products, Inc.
PARTTEMP RANGEPIN-
PACKAGE
TOP
MARK
MAX4036EXK-T-40°C to +85°C5 SC70AFR
MAX4036AAXK+T -40°C to +125°C5 SC70ASN
MAX4037EUT-T-40°C to +85°C6 SOT23ABRX
MAX4038ETA-T-40°C to +85°C8 TDFN-EP*AGO
MAX4038EUA-40°C to +85°C8 µMAX—
MAX4038EBL-T-40°C to +85°C9 UCSPAEG
MAX4038AAUA -40°C to +125°C8 µMAX—
Pin Configurations and Selector Guide appear at end of
data sheet.
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VDD= +3V, VSS= VCM= 0V, VOUT_= VDD/2, RLto VDD/2, CL= 15pF, TA= +25°C,unless otherwise specified.)
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.
VDDto VSS.............................................................-0.3V to +4.0V
INA+, INB+, INA-, INB-, IN+, IN-, OUTA,
OUTB, OUT, REF.........................(VSS- 0.3V) to (VDD+ 0.3V)
OUTA, OUTB, OUT, REF Shorted to VSSor VDD.......Continuous
Maximum Continuous Power Dissipation (TA= +70°C)
5-Pin SC70 (derate 3.1mW/°C above +70°C)..............247mW
6-Pin SOT23 (derate 8.7mW/°C above +70°C)............696mW
8-Pin µMAX (derate 4.5mW/°C above +70°C).............362mW
8-Pin TDFN (derate 24.4mW/°C above +70°C).........1951mW
9-Bump UCSP (derate 5.2mW/°C above +70°C).........412mW
10-Pin µMAX (derate 5.6mW/°C above +70°C)...........444mW
10-Pin TDFN(derate 24.4mW/°C above +70°C).......1951mW
Operating Temperature Range
MAX403_E_ _...................................................-40°C to +85°C
MAX403_A_ _................................................-40°C to +125°C
Junction Temperature .....................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
MAX4036/MAX4038, guaranteed by PSRR
tests1.43.6
Supply Voltage RangeVDD
MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests1.83.6
VDD = 1.4V0.81.2MAX4036VDD = 3.6V0.91.3
VDD = 1.8V1.92.4MAX4037VDD = 3.6V2.02.5
VDD = 1.4V1.72.3MAX4038VDD = 3.6V1.92.5
VDD = 1.8V2.84.0
Supply CurrentIDD
MAX4039VDD = 3.6V3.04.1
OPERATIONAL AMPLIFIERS
Input Offset VoltageVOS±0.2±2.0mV
Input Bias CurrentIB(Note 1)±1.0±10pA
Input Offset CurrentIOS(Note 1)±0.3±20pAD D = 1.4V M AX 4036/M AX 4038 onl y) VSSVDD -
VDD = 1.8VVSSVDD -
Input Common-Mode Voltage
RangeVCMGuaranteed by
CMRR test
VDD = 3.3VVSSVDD -
VDD = 1.4V, VSS ≤ VCM ≤ (VDD - 0.4V)
(MAX4036/MAX4038 only)5070
VDD = 1.8V, VSS ≤ VCM ≤ (VDD - 0.3V)5070Common-Mode Rejection RatioCMRR
VDD = 3.3V, VSS ≤ VCM ≤ (VDD - 0.2V)5676
1.4V ≤ VDD ≤ 3.6V (MAX4036/MAX4038
only)6282Power-Supply Rejection RatioPSRR
1.8V ≤ VDD ≤ 3.6V6284
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
ELECTRICAL CHARACTERISTICS (continued)
(VDD= +3V, VSS= VCM= 0V, VOUT_= VDD/2, RLto VDD/2, CL= 15pF, TA= +25°C,unless otherwise specified.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
RL = 100kΩ, 50mV ≤ VOUT ≤ (VDD - 50mV)80108Large-Signal Voltage GainAVOLRL = 5kΩ, 150mV ≤ VOUT ≤ (VDD - 150mV)78105dB
RL = 100kΩ25Output Voltage Swing HighVDD - VOHRL = 5kΩ2550mV
RL = 100kΩ25Output Voltage Swing LowVOL - VSSRL = 5kΩ2550mV
Output Short-Circuit CurrentISCOTo VDD or VSS±13mA
Gain-Bandwidth ProductGBW4kHz
Phase MarginθM90Degrees
Slew RateSR4V/ms
Power-On TimetON(Note 3)0.25ms
Input Noise-Voltage Densityenf = 1kHz500nV/√Hz
Capacitive-Load StabilityCLOADAVCL = 1V/V, no sustained oscillations5000pF
REFERENCE (MAX4037/MAX4039)
Reference VoltageVREF1.2261.2321.238V
Line RegulationΔVREF/
ΔVDDVDD = +1.8V to +3.6V0.3%/V
0 ≤ ILOAD ≤ 100µA, sourcing0.0015Load Regulation
ΔVREF/
ΔILOAD-20µA ≤ ILOAD ≤ 0, sinking0.0075%/µA
Reference Output Voltage Noiseen0.1Hz to 10Hz60µVP-P
Short to VDD0.25Output Short-Circuit CurrentISCRShort to VSS1.9mA
Capacitive-Load Stability RangeCLOAD(Note 1)0250pF
ELECTRICAL CHARACTERISTICS
(VDD= +3V, VSS= VCM= 0V, VOUT_= VDD/2, RLto VDD/2, CL= 15pF, TA= TMINto TMAX,unless otherwise specified.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
MAX4036/MAX4038, guaranteed by PSRR
test1.43.6
Supply Voltage RangeVDD
MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests1.83.6
VDD = 1.4V1.7MAX4036VDD = 3.6V1.8
VDD = 1.4V2.0MAX4036AVDD = 3.6V2.1
VDD = 1.8V3.1
Supply CurrentIDD
MAX4037VDD = 3.6V3.2
ELECTRICAL CHARACTERISTICS (continued)
(VDD= +3V, VSS= VCM= 0V, VOUT_= VDD/2, RLto VDD/2, CL= 15pF, TA= TMINto TMAX,unless otherwise specified.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
VDD = 1.4V2.9
MAX4038VDD = 3.6V3.2
VDD = 1.4V3.4MAX4038AVDD = 3.6V3.7
VDD = 1.8V5.2
Supply CurrentIDD
MAX4039VDD = 3.6V5.3
OPERATIONAL AMPLIFIERS
Input Offset VoltageVOS±8mV
Input Offset Voltage Temperature
CoefficientTCVOS±1µV/°C
Input Bias CurrentIB±100pA
Input Offset CurrentIOS±200pA
VDD = 1.4V
(MAX4036/MAX4038 only)VSSVDD -
VDD = 1.8VVSSVDD -
Input Common-Mode Voltage
RangeVCMGuaranteed by
CMRR test
VDD = 3.3VVSSVDD -
VDD = 1.4V, VSS ≤ VCM ≤ (VDD - 0.5V)
(MAX4036/MAX4038 only)44
VDD = 1.8V, VSS ≤ VCM ≤ (VDD - 0.4V)50Common-Mode Rejection RatioCMRR
VDD = 3.3V, VSS ≤ VCM ≤ (VDD - 0.3V)52
1.4V ≤ VDD ≤ 3.6V
(MAX4036/MAX4038 only)60Power-Supply Rejection RatioPSRR
1.8V ≤ VDD ≤ 3.6V60
RL = 100kΩ, 50mV ≤ VOUT ≤ (VDD - 50mV)75Large-Signal Voltage GainAVOL
RL = 5kΩ, 150mV ≤ VOUT ≤ (VDD - 150mV)73
RL = 100kΩ10Output Voltage Swing HighVDD - VOHRL = 5kΩ100mV
RL = 100kΩ10Output Voltage Swing LowVOL - VSSRL = 5kΩ100mV
REFERENCE (MAX4037/MAX4039)
MAX4037EUT-T, MAX4039ETB,
MAX4039EUB25120Reference Voltage Temperature
CoefficientTCVREF(Note 1)
MAX4039EBL-T35200
ppm/°C
Line RegulationΔVREF/
ΔVDDVDD = 1.8V to 3.6V0.6%/V
0 ≤ ILOAD ≤ 100µA, sourcing0.003Load RegulationΔVREF/
ΔILOAD-20µA ≤ ILOAD ≤ 0, sinking0.015%/µA
Capacitive-Load Stability RangeCLOAD(Note 1)0250pF
Note 1:Guaranteed by design.
Note 2:All devices are production tested at TA= +25°C. All temperature limits are guaranteed by design.
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
MAX4036
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX4036 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TA = +85°C
TA = -40°C
TA = +25°C
MAX4037
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX4036 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TA = +85°C
TA = -40°C
TA = +25°C
MAX4038
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX4036 toc03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TA = +85°C
TA = -40°C
TA = +25°C
MAX4039
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX4036 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (
TA = +85°C
TA = -40°C
TA = +25°C
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
MAX4036 toc05
COMMON-MODE VOLTAGE (V)
OFFSET VOLTAGE (mV)1
VDD = 1.4V
VDD = 1.8VVDD = 3.0V
OFFSET VOLTAGE
vs. TEMPERATURE
MAX4036 toc06
TEMPERATURE (°C)
OFFSET VOLTAGE (mV)3510-15
INPUT BIAS CURRENT
vs. TEMPERATURE
MAX4036 toc07
INPUT BIAS CURRENT (pA)3510-15
VCM = 3V
VCM = 0V
INPUT BIAS CURRENT
vs. COMMON-MODE VOLTAGE
MAX4036 toc08
INPUT BIAS CURRENT (pA)
TA = +25°C
TA = +85°C
-10010k1k100
OP AMP POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX4036 toc09
PSRR (dB)
AV = 1V/V
Typical Operating Characteristics
(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
OUTPUT VOLTAGE SWING HIGH
vs. TEMPERATURE
MAX4036 toc10
TEMPERATURE (°C)
- V
(mV)3510-15
RL = 5kΩ
RL = 100kΩ
OUTPUT VOLTAGE SWING LOW
vs. TEMPERATURE
MAX4036 toc11
TEMPERATURE (°C)
- V
(mV)3510-15
RL = 100kΩ
RL = 5kΩ
AV
vs. OUTPUT SWING LOW
MAX4036 toc12
VOL (mV)
(dB)
RL = 5kΩ
RL = 100kΩ
AV
vs. OUTPUT SWING HIGH
MAX4036 toc13
VDD - VOH (mV)
(dB)
RL = 5kΩ
RL = 100kΩ
AV
vs. TEMPERATURE
MAX4036 toc14
TEMPERATURE (°C)
VOL
(dB)3510-15
RL = 100kΩRL = 5kΩ
-1000.110k100k
CROSSTALK
vs. FREQUENCY
MAX4036 toc15
FREQUENCY (Hz)
CROSSTALK (dB)
RL = 5kΩ
RL = 100kΩ
AV = 1V/V
MAX4038/MAX4039
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX4036 toc16
THD+N (%)
AV = 1V/V
VIN_ = VDD/2
VOUT = 2.5VP-P
RL = 100kΩ TO VSS
VOUT = 2.5VP-P
RL = 5kΩ TO VSS
100,000
10k100k1M
OP AMP STABILITY
vs. CAPACITIVE AND RESISTIVE LOADS
MAX4036 toc17
CAPACITIVE LOAD (pF)
10,000
STABLE
REGIONRL TO VSS
UNSTABLE
REGION
OP AMP SINK CURRENT
vs. OUTPUT VOLTAGE
MAX4036 toc18
SINK CURRENT (mA)
VDD = 3.0V
VDD = 1.8V
VID = -100mV
Typical Operating Characteristics (continued)
(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
OP AMP SOURCE CURRENT
vs. OUTPUT VOLTAGE
MAX4036 toc19
VOUT_ (V)
SOURCE CURRENT (mA)
VDD = 3.0V
VDD = 1.8V
VID = +100mV
INPUT VOLTAGE NOISE DENSITY
vs. FREQUENCY
MAX4036 toc20
FREQUENCY (Hz)
INPUT VOLTAGE NOISE (nV/
Hz)100101
0.110k
OP AMP
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4036 toc21
2.55V
2.45V
2.55V
2.45V
VIN+
VOUT_
AV = 1V/V
CL = 12pF TO VSS
RL = 1MΩ TO VSS
OP AMP
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4036 toc22
40µs/div
AV = 1V/V
CL = 250pF TO VSS
RL = 1MΩ TO VSS
VIN+
VOUT_
2.55V
2.45V
2.55V
2.45V
OP AMP
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4036 toc23
100µs/div
AV = 1V/V
CL = 12pF TO VSS
RL = 1MΩ TO VSS
VIN+
VOUT_
500mV/div
2.5V
1.5V
OP AMP
TURN-ON TRANSIENT RESPONSE
MAX4036 toc24
100µs/div
3.0V
VOUT_
50mV/div
AV = 1V/V
CL = 12pF TO GND
RL = 1MΩ TO GND
VIN+ = VDD / 2
VDD
Typical Operating Characteristics (continued)
(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
-40101001k10k100k
GAIN AND PHASE
vs. FREQUENCY
MAX4036 toc25
FREQUENCY (Hz)
GAIN (dB)
PHASE (DEGREES)
AV = 1000V/V
VIN_ = 1mVP-P
GAIN
PHASE
10010k100k
LARGE-SIGNAL GAIN
vs. FREQUENCY
MAX4036 toc26
FREQUENCY (Hz)
GAIN (dB)
RL = 1MΩ
AV = 1
VOUT_ = 1VP-P
CL = 12pF
RL = 100kΩ
RL = 5kΩ
REFERENCE VOLTAGE
vs. TEMPERATURE
MAX4036 toc27
TEMPERATURE (°C)
REF
(V)3510-15
MAX4037/MAX4039
REFERENCE VOLTAGE CHANGE
vs. TIME
MAX4036 toc28
TIME (HR)
REF
(V)
MAX4037
MAX4039
REFERENCE VOLTAGE CHANGE
vs. LOAD CURRENT
MAX4036 toc29
LOAD CURRENT (µA)
NORMALIZED V
REF
TA = +85°C
TA = +25°C
TA = -40°C
REFERENCE VOLTAGE CHANGE
vs. SUPPLY VOLTAGE
MAX4036 toc30
NORMALIZED V
REF
TA = +85°C
TA = +25°C
TA = -40°C
Typical Operating Characteristics (continued)
(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)
REFERENCE LINE-TRANSIENT RESPONSE
MAX4036 toc31
1ms/div
VDD
VREF
AC-COUPLED
50mV/div
1.8V
3.6V
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
REFERENCE LOAD-TRANSIENT RESPONSE
(SINKING CURRENT)
MAX4036 toc32
2.5ms/div
VREF
500mV/div
2µA
IREF
MAX4036 toc33
2.5ms/div
20µA
IREF
VREF
500mV/div
REFERENCE LOAD-TRANSIENT RESPONSE
(SINKING CURRENT)
REFERENCE LOAD-TRANSIENT RESPONSE
(SOURCING CURRENT)
MAX4036 toc34
1ms/div
IREF
10µA
VREF
500mV/div
MAX4036 toc35
1ms/div
IREF
100µA
VREF
500mV/div
REFERENCE LOAD-TRANSIENT RESPONSE
(SOURCING CURRENT)
REFERENCE TURN-ON
TRANSIENT RESPONSE
MAX4036 toc36
1ms/div
VDD
VREF
0.1Hz TO 10Hz REFERENCE NOISE
MAX4036 toc37
1s/div
Typical Operating Characteristics (continued)
(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
Detailed Description
The MAX4036–MAX4039 consume an ultra-low supply
current and have rail-to-rail output stages specifically
designed for low-voltage operation. The input common-
mode voltage range extends from VDD- 0.4V to VSS,
although full rail-to-rail input range is possible with
degraded performance when operating from a supply
voltage above 3.0V. The input offset voltage is typically
200µV. Low-operating supply voltage, low supply current,
and rail-to-rail outputs make the MAX4036–MAX4039 an
excellent choice for precision or general-purpose low-
voltage, battery-powered systems.
Rail-to-Rail Outputs
The MAX4036–MAX4039 output stages can drive a 5kΩ
load and still swing to within 40mV of the rails. Figure 1
shows the output voltage swing of the MAX4036–
MAX4039 configured as a unity-gain buffer, powered
from a single 2.4V supply. The output for this setup typi-
cally swings from 5mV to VDD- 5mV with a 100kΩload.
PIN
MAX4038/
MAX4038AMAX4039MAX4036/
MAX4036AMAX4037
µMAX*/TDFNUCSPµMAX/TDFUCSP
NAMEFUNCTION3————IN+Noninverting Amplifier Input24A25A2VSSNegative Power-Supply Voltage4————IN-Inverting Amplifier Input1————OUTAmplifier Output8C210C2VDDPositive Power-Supply Voltage5——6B2REFReference Voltage Output—1C11C1OUTAAmplifier Output (Channel A)—2B12B1INA-Inverting Amplifier Input (Channel A)—3A13A1INA+Noninverting Amplifier Input (Channel A)—5A37A3INB+Noninverting Amplifier Input (Channel B)—6B38B3INB-Inverting Amplifier Input (Channel B)—7C39C3OUTBAmplifier Output (Channel B)——B24—N.C.No Connection. Not internally connected.————EP
(TDFN only)
Exposed Paddle. Solder EP to VSS or leave
unconnected (TDFN packages only).
2ms/div
1V/div
VIN_+1.5V
1.5VVOUT+
AV = 1V/V
Figure 1. Rail-to-Rail Input/Output Voltage Range
*Both MAX4038/MAX4038A available in µMAX package only.
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
Applications Information
Power-Supply Considerations
The MAX4036–MAX4039 operate from a single 1.4V
(MAX4036/MAX4038) or 1.8V (MAX4037/MAX4039) to
3.6V supply. A high amplifier power-supply rejection
ratio of 82dB and the excellent reference line regulation
allow the devices to be powered directly from a decay-
ing battery voltage, simplifying design and extending
battery life. The MAX4036–MAX4039 are ideally suited
for low-voltage battery-powered systems. The Typical
Operating Characteristicsshow the changes in supply
current and reference output as a function of supply
voltage.
Power-Up Settling Time
The MAX4036–MAX4039 typically require 0.25ms to
power-up. During this startup time, the output is inde-
terminate. The application circuit should allow for this
initial delay. See the Typical Operating Characteristics
for amplifier and reference settling time curves.
Driving Capacitive Loads: Op Amps
The MAX4036–MAX4039 amplifier(s) require no output
capacitor for stability, and are unity-gain stable for
loads up to 5000pF. Applications that require greater
capacitive-drive capability should use an isolation
resistor between the output and the capacitive load
(Figure 2). Note that this solution reduces the gain and
output voltage swing because RISOforms a voltage-
divider with the load resistor.
Crossover Distortion
The MAX4036–MAX4039 output stages are capable of
sourcing and sinking currents with orders of magnitude
greater than the stages’ quiescent current, which is
less than 1µA. This ability to drive heavy loads with
such a small quiescent current introduces crossover
distortion as the output stage passes between sinking
and sourcing. In the crossover regions, the output
impedance of the MAX4036–MAX4039 increases sub-
stantially, thereby changing the load-driving character-
istics. The distortion can be greatly reduced by
increasing the load resistance. For applications where
low load resistance is required, bias the load such that
the output current is always in one direction, to avoid
crossover distortion.
Reference Bypassing
The MAX4037/MAX4039 reference requires no external
capacitors.
Using the MAX4036–MAX4039 as a
Comparator
Although optimized for use as an operational amplifier,
the MAX4036–MAX4039 can be used as a rail-to-rail
I/O comparator (Figures 3, 4). External hysteresis can
be used to minimize the risk of output oscillation. The
positive feedback circuit, shown in Figure 4, causes the
input threshold to change when the output voltage
changes state.
Battery Monitoring Using the
MAX4037/MAX4039 and Hysteresis
The internal reference and low operating voltage of the
MAX4037/MAX4039 make the devices ideal for battery-
monitoring applications. Hysteresis can be set using
resistors as shown in Figure 4, and the following design
procedure:Choose R3. The input bias current of IN_+ is under
100pA over temperature, so a current through R3
around 100nA maintains accuracy. The current
through R3 at the trip point is VREF / R3, or 100nA
for R3 = 12MΩ. 10MΩis a good practical value.Choose the hysteresis voltage (VHB), the voltage
between the upper and lower thresholds. In this
example, choose VHB= 50mV (see Figure 3).
MAX4038
RISOCL
RL + RISOAV == 1
Figure 2. Using a Resistor to Isolate a Capacitive Load from
VHB
VOH
VOL
VTHR
VTHF
INPUT
OUTPUT
Figure 3. Hysteresis

Partno	Mfg	Dc	Qty	Available	Descript
MAX4037EUT	MAXIM ?	N/a	40	avai	Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps with +1.2V Buffered Reference