19-3142; Rev 5; 11/09
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
Features
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 reference. 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 reference 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.
♦ Ultra-Low 800nA per Amplifier Supply Current
♦ Ultra-Low 1.4V Supply Voltage Operation (1.8V for
MAX4037/MAX4039)
♦ Rail-to-Rail Outputs Drive 5kΩ and 5000pF Load
♦ 1.232V ±0.5%, 120ppm/°C (max) Reference
(MAX4037/MAX4039)
♦ No External Reference Bypass Capacitor
Required
♦ No Phase Reversal for Overdriven Inputs
♦ Low 1.0pA (typ) Input Bias Current
♦ Low 200μV Input Offset Voltage
♦ Unity-Gain Stable
♦ Available in Tiny UCSP, SC70, SOT23, TDFN, and
μMAX Packages
♦ Available in -40°C to +125°C Temperature Range
(MAX4036A/MAX4038A)
Ordering Information
Applications
Battery-Powered/Solar-Powered Systems
TEMP RANGE
PINPACKAGE
MAX4036EXK-T
-40°C to +85°C
5 SC70
MAX4036AAXK+T
-40°C to +125°C
5 SC70
MAX4037EUT-T
-40°C to +85°C
6 SOT23
ABRX
MAX4038ETA-T
-40°C to +85°C
8 TDFN-EP*
AGO
PART
Portable Medical Instrumentation
Pagers and Cell Phones
Micropower Thermostats and Potentiostats
Electrometer Amplifiers
TOP
MARK
AFR
ASN
Remote Sensor Amplifiers
MAX4038EUA
-40°C to +85°C
8 µMAX
—
Active Badges
MAX4038EBL-T
-40°C to +85°C
9 UCSP
AEG
pH Meters
MAX4038AAUA
-40°C to +125°C
8 µMAX
—
Pin Configurations and Selector Guide appear at end of
data sheet.
µMAX is a registered trademark and UCSP is a trademark of
Maxim Integrated Products, Inc.
+Denotes a lead(Pb)-free/RoHS-compliant package.
-Denotes a package containing lead.
*EP = Exposed pad.
Ordering Information continued at end of data sheet.
Functional Diagram
Typical Operating Circuit
3V
OUTA
MAX4039
VDD
INAOUTA
VDD
OUTB
INA-
INB-
INA+
REF
INB+
INB+
SENSOR
MAX4039
INB-
INA+
REF
OUTB
REF
VSS
ADC
VSS
THREE-ELECTRODE POTENTIOSTAT APPLICATION
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX4036–MAX4039
General Description
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
ABSOLUTE MAXIMUM RATINGS
VDD to 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 VSS or 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
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.
ELECTRICAL CHARACTERISTICS
(VDD = +3V, VSS = VCM = 0V, VOUT_ = VDD/2, RL to VDD/2, CL = 15pF, TA = +25°C, unless otherwise specified.)
PARAMETER
Supply Voltage Range
SYMBOL
VDD
CONDITIONS
TYP
MAX
MAX4036/MAX4038, guaranteed by PSRR
tests
1.4
3.6
MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests
1.8
3.6
UNITS
V
MAX4036
MAX4037
Supply Current
MIN
IDD
MAX4038
MAX4039
VDD = 1.4V
0.8
1.2
VDD = 3.6V
0.9
1.3
VDD = 1.8V
1.9
2.4
VDD = 3.6V
2.0
2.5
VDD = 1.4V
1.7
2.3
µA
VDD = 3.6V
1.9
2.5
VDD = 1.8V
2.8
4.0
VDD = 3.6V
3.0
4.1
±0.2
±2.0
mV
OPERATIONAL AMPLIFIERS
Input Offset Voltage
Input Bias Current
Input Offset Current
Input Common-Mode Voltage
Range
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
2
VOS
IB
(Note 1)
±1.0
±10
pA
IOS
(Note 1)
±0.3
±20
pA
VCM
CMRR
PSRR
Guaranteed by
CMRR test
VDD = 1.4V
(MAX4036/MAX4038 only)
VSS
VDD 0.4
VDD = 1.8V
VSS
VDD 0.3
VDD = 3.3V
VSS
VDD 0.2
VDD = 1.4V, VSS ≤ VCM ≤ (VDD - 0.4V)
(MAX4036/MAX4038 only)
50
70
VDD = 1.8V, VSS ≤ VCM ≤ (VDD - 0.3V)
50
70
VDD = 3.3V, VSS ≤ VCM ≤ (VDD - 0.2V)
56
76
1.4V ≤ VDD ≤ 3.6V (MAX4036/MAX4038
only)
62
82
1.8V ≤ VDD ≤ 3.6V
62
84
_______________________________________________________________________________________
V
dB
dB
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
(VDD = +3V, VSS = VCM = 0V, VOUT_ = VDD/2, RL to VDD/2, CL = 15pF, TA = +25°C, unless otherwise specified.)
PARAMETER
SYMBOL
Large-Signal Voltage Gain
AVOL
Output Voltage Swing High
VDD - VOH
Output Voltage Swing Low
VOL - VSS
CONDITIONS
MIN
TYP
RL = 100kΩ, 50mV ≤ VOUT ≤ (VDD - 50mV)
80
108
RL = 5kΩ, 150mV ≤ VOUT ≤ (VDD - 150mV)
78
105
MAX
dB
RL = 100kΩ
2
5
RL = 5kΩ
25
50
RL = 100kΩ
2
5
RL = 5kΩ
25
50
mV
mV
Output Short-Circuit Current
ISCO
±13
mA
Gain-Bandwidth Product
GBW
4
kHz
Phase Margin
θM
90
Degrees
Slew Rate
SR
4
V/ms
Power-On Time
tON
(Note 3)
0.25
ms
en
f = 1kHz
500
nV/√Hz
AVCL = 1V/V, no sustained oscillations
5000
pF
Input Noise-Voltage Density
Capacitive-Load Stability
CLOAD
To VDD or VSS
UNITS
REFERENCE (MAX4037/MAX4039)
Reference Voltage
VREF
Line Regulation
ΔVREF/
ΔVDD
Load Regulation
ΔVREF/
ΔILOAD
Reference Output Voltage Noise
Output Short-Circuit Current
Capacitive-Load Stability Range
en
ISCR
CLOAD
1.226
1.232
VDD = +1.8V to +3.6V
1.238
V
0.3
%/V
0 ≤ ILOAD ≤ 100µA, sourcing
0.0015
-20µA ≤ ILOAD ≤ 0, sinking
0.0075
0.1Hz to 10Hz
60
Short to VDD
0.25
Short to VSS
1.9
(Note 1)
0
%/µA
µVP-P
mA
250
pF
ELECTRICAL CHARACTERISTICS
(VDD = +3V, VSS = VCM = 0V, VOUT_ = VDD/2, RL to VDD/2, CL = 15pF, TA = TMIN to TMAX, unless otherwise specified.) (Note 2)
PARAMETER
Supply Voltage Range
SYMBOL
VDD
CONDITIONS
IDD
TYP
MAX
1.4
3.6
MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests
1.8
3.6
UNITS
V
MAX4036
Supply Current
MIN
MAX4036/MAX4038, guaranteed by PSRR
test
MAX4036A
MAX4037
VDD = 1.4V
1.7
VDD = 3.6V
1.8
VDD = 1.4V
2.0
VDD = 3.6V
2.1
VDD = 1.8V
3.1
VDD = 3.6V
3.2
µA
_______________________________________________________________________________________
3
MAX4036–MAX4039
ELECTRICAL CHARACTERISTICS (continued)
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, RL to VDD/2, CL = 15pF, TA = TMIN to TMAX, unless otherwise specified.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MAX4038
Supply Current
IDD
MAX4038A
MAX4039
MIN
TYP
MAX
VDD = 1.4V
2.9
VDD = 3.6V
3.2
VDD = 1.4V
3.4
VDD = 3.6V
3.7
VDD = 1.8V
5.2
VDD = 3.6V
5.3
UNITS
µA
OPERATIONAL AMPLIFIERS
Input Offset Voltage
VOS
Input Offset Voltage Temperature
Coefficient
±8
±1
TCVOS
Input Bias Current
Input Offset Current
Input Common-Mode Voltage
Range
±100
pA
IOS
±200
pA
CMRR
Power-Supply Rejection Ratio
PSRR
Large-Signal Voltage Gain
µV/°C
IB
VCM
Common-Mode Rejection Ratio
mV
AVOL
Output Voltage Swing High
VDD - VOH
Output Voltage Swing Low
VOL - VSS
Guaranteed by
CMRR test
VDD = 1.4V
(MAX4036/MAX4038 only)
VSS
VDD 0.4
VDD = 1.8V
VSS
VDD 0.4
VDD = 3.3V
VSS
VDD 0.2
VDD = 1.4V, VSS ≤ VCM ≤ (VDD - 0.5V)
(MAX4036/MAX4038 only)
44
VDD = 1.8V, VSS ≤ VCM ≤ (VDD - 0.4V)
50
VDD = 3.3V, VSS ≤ VCM ≤ (VDD - 0.3V)
52
1.4V ≤ VDD ≤ 3.6V
(MAX4036/MAX4038 only)
60
1.8V ≤ VDD ≤ 3.6V
60
RL = 100kΩ, 50mV ≤ VOUT ≤ (VDD - 50mV)
75
RL = 5kΩ, 150mV ≤ VOUT ≤ (VDD - 150mV)
73
V
dB
dB
dB
RL = 100kΩ
10
RL = 5kΩ
100
RL = 100kΩ
10
RL = 5kΩ
100
mV
mV
REFERENCE (MAX4037/MAX4039)
MAX4037EUT-T, MAX4039ETB,
MAX4039EUB
MAX4039EBL-T
25
120
35
200
Reference Voltage Temperature
Coefficient
TCVREF
Line Regulation
ΔVREF/
ΔVDD
Load Regulation
ΔVREF/
ΔILOAD
0 ≤ ILOAD ≤ 100µA, sourcing
0.003
-20µA ≤ ILOAD ≤ 0, sinking
0.015
Capacitive-Load Stability Range
CLOAD
(Note 1)
(Note 1)
VDD = 1.8V to 3.6V
0.6
0
Note 1: Guaranteed by design.
Note 2: All devices are production tested at TA = +25°C. All temperature limits are guaranteed by design.
Note 3: Output settles within 1% of final value.
4
_______________________________________________________________________________________
250
ppm/°C
%/V
%/µA
pF
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
MAX4037
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
TA = +25°C
0.8
TA = -40°C
0.4
TA = +25°C
2.5
2.0
1.5
TA = -40°C
1.0
3.0
0.5
1.4
1.8
2.2
2.6
3.0
1.5
1.0
TA = -40°C
2.1
2.4
2.7
3.0
3.3
0
3.6
1.4
1.8
2.2
2.6
3.0
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
MAX4039
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
OFFSET VOLTAGE
vs. TEMPERATURE
2
TA = -40°C
0.6
VDD = 1.8V
VDD = 3.0V
VDD = 1.4V
0.4
0.2
1
2.1
2.4
2.7
3.0
3.3
-0.10
2
3
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
TEMPERATURE (°C)
INPUT BIAS CURRENT
vs. TEMPERATURE
INPUT BIAS CURRENT
vs. COMMON-MODE VOLTAGE
OP AMP POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
20
VCM = 3V
10
0
VCM = 0V
-15
10
35
TEMPERATURE (°C)
-30
TA = +85°C
20
85
-40
-50
-60
-70
10
-80
-90
-100
0
60
-20
30
TA = +25°C
-10
AV = 1V/V
-10
PSRR (dB)
INPUT BIAS CURRENT (pA)
30
0
MAX4036 toc09
40
MAX4036 toc07
40
-40
0
-0.30
1
0
3.6
MAX4036 toc08
1.8
0.10
-0.20
0
0
MAX4036 toc06
0.20
OFFSET VOLTAGE (mV)
3
3.4
0.30
MAX4036 toc05
0.8
OFFSET VOLTAGE (mV)
TA = +25°C
1.0
MAX4036 toc04
TA = +85°C
4
INPUT BIAS CURRENT (pA)
2.0
SUPPLY VOLTAGE (V)
5
SUPPLY CURRENT (μA)
1.8
3.4
TA = +25°C
0.5
0
0
TA = +85°C
2.5
SUPPLY CURRENT (μA)
TA = +85°C
1.2
TA = +85°C
MAX4036 toc02
MAX4036 toc01
3.0
SUPPLY CURRENT (μA)
SUPPLY CURRENT (μA)
1.6
MAX4038
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
MAX4036 toc03
MAX4036
SUPPLY CURRENT
vs. SUPPLY VOLTAGE AND TEMPERATURE
0
0.5
1.0
1.5
2.0
2.5
COMMON-MODE VOLTAGE (V)
3.0
10
100
1k
10k
FREQUENCY (Hz)
_______________________________________________________________________________________
5
MAX4036–MAX4039
Typical Operating Characteristics
(VDD = 3V, VSS = VCM = 0V, RL to VDD/2, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VDD = 3V, VSS = VCM = 0V, RL to VDD/2, TA = +25°C, unless otherwise noted.)
30
25
VOL - VSS (mV)
RL = 5kΩ
100
20
15
10
RL = 5kΩ
120
AV (dB)
15
140
MAX4036 toc11
RL = 5kΩ
20
RL = 100kΩ
80
10
60
5
5
RL = 100kΩ
0
RL = 100kΩ
0
-15
10
35
60
85
40
-40
-15
10
35
60
85
0
100
200
300
400
TEMPERATURE (°C)
TEMPERATURE (°C)
VOL (mV)
AV
vs. OUTPUT SWING HIGH
AV
vs. TEMPERATURE
CROSSTALK
vs. FREQUENCY
140
MAX4036 toc13
140
RL = 5kΩ
120
0
120
500
MAX4036 toc15
-40
MAX4036 toc14
VDD - VOH (mV)
35
MAX4036 toc10
30
25
AV
vs. OUTPUT SWING LOW
OUTPUT VOLTAGE SWING LOW
vs. TEMPERATURE
MAX4036 toc12
OUTPUT VOLTAGE SWING HIGH
vs. TEMPERATURE
MAX4038/MAX4039
AV = 1V/V
-20
100
RL = 100kΩ
80
RL = 100kΩ
CROSSTALK (dB)
AV (dB)
AVOL (dB)
RL = 5kΩ
100
80
60
-40
RL = 5kΩ
-60
RL = 100kΩ
40
-80
60
20
0
0
100
200
300
400
-100
-40
500
-15
35
60
85
0
1k
0.1
10k
TEMPERATURE (°C)
FREQUENCY (Hz)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
OP AMP STABILITY
vs. CAPACITIVE AND RESISTIVE LOADS
OP AMP SINK CURRENT
vs. OUTPUT VOLTAGE
100,000
UNSTABLE
REGION
1
VOUT = 2.5VP-P
RL = 5kΩ TO VSS
0.1
10,000
1000
VOUT = 2.5VP-P
RL = 100kΩ TO VSS
STABLE
REGION
0.01
0.1
1
FREQUENCY (kHz)
10
100
VDD = 3.0V
100k
10
8
6
VDD = 1.8V
4
2
RL TO VSS
0
100
0.01
VID = -100mV
12
SINK CURRENT (mA)
CAPACITIVE LOAD (pF)
10
14
MAX4036 toc17
AV = 1V/V
VIN_ = VDD/2
MAX4036 toc16
VDD - VOH (mV)
100
6
10
MAX4036 toc18
40
THD+N (%)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
10k
100k
RESISTIVE LOAD (Ω)
1M
0
0.6
1.2
1.8
VOUT_ (V)
_______________________________________________________________________________________
2.4
3.0
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
INPUT VOLTAGE NOISE DENSITY
vs. FREQUENCY
OP AMP SOURCE CURRENT
vs. OUTPUT VOLTAGE
SOURCE CURRENT (mA)
14
VDD = 3.0V
12
10
8
6
VDD = 1.8V
4
MAX4036 toc20
INPUT VOLTAGE NOISE (nV/√Hz)
VID = +100mV
16
3500
MAX4036 toc19
18
3000
2500
2000
1500
1000
500
2
0
0
0
0.6
1.2
1.8
2.4
3.0
0.1
1
10
100
1k
10k
FREQUENCY (Hz)
VOUT_ (V)
OP AMP
SMALL-SIGNAL TRANSIENT RESPONSE
AV = 1V/V
CL = 250pF TO VSS
RL = 1MΩ TO VSS
2.55V
MAX4036 toc22
MAX4036 toc21
AV = 1V/V
CL = 12pF TO VSS
RL = 1MΩ TO VSS
2.55V
OP AMP
SMALL-SIGNAL TRANSIENT RESPONSE
VIN+
VIN+
2.45V
2.45V
2.55V
2.55V
VOUT_
2.45V
VOUT_
2.45V
40μs/div
OP AMP
LARGE-SIGNAL TRANSIENT RESPONSE
VIN+
1.5V
AV = 1V/V
CL = 12pF TO GND
RL = 1MΩ TO GND
VIN+ = VDD / 2
MAX4036 toc24
MAX4036 toc23
AV = 1V/V
CL = 12pF TO VSS
RL = 1MΩ TO VSS
2.5V
OP AMP
TURN-ON TRANSIENT RESPONSE
3.0V
VDD
0V
VOUT_
500mV/div
100μs/div
VOUT_
50mV/div
100μs/div
________________________________________________________________________________________
7
MAX4036–MAX4039
Typical Operating Characteristics (continued)
(VDD = 3V, VSS = VCM = 0V, RL to VDD/2, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VDD = 3V, VSS = VCM = 0V, RL to VDD/2, TA = +25°C, unless otherwise noted.)
GAIN AND PHASE
vs. FREQUENCY
GAIN
180
2
135
-2
-6
PHASE
0
-45
-20
-30
-40
1
10
100
1k
RL = 5kΩ
RL = 100kΩ
-22
AV = 1
VOUT_ = 1VP-P
CL = 12pF
-26
-135
100k
10k
RL = 1MΩ
-14
-18
-90
AV = 1000V/V
VIN_ = 1mVP-P
-10
-30
100
REFERENCE VOLTAGE CHANGE
vs. TIME
REFERENCE VOLTAGE CHANGE
vs. LOAD CURRENT
1.02
MAX4036 toc28
1.234
1.234
MAX4036 toc27
MAX4037/MAX4039
TA = +85°C
1.233
1.230
MAX4037
1.232
MAX4039
1.231
1.230
-15
10
35
60
0.98
0
85
100
200
300
400
500
600
-100
TIME (HR)
TEMPERATURE (°C)
REFERENCE VOLTAGE CHANGE
vs. SUPPLY VOLTAGE
1.0002
0
100
1.0001
3.6V
VDD
1.8V
1.0000
0.9999
0V
0.9998
TA = -40°C
VREF
AC-COUPLED
50mV/div
TA = +25°C
0.9997
TA = +85°C
0.9996
0.9995
1.8
2.1
2.4
2.7
3.0
3.3
3.6
1ms/div
VDD (V)
8
200
300
LOAD CURRENT (μA)
REFERENCE LINE-TRANSIENT RESPONSE
MAX4036 toc30
1.0003
NORMALIZED VREF
1.00
MAX4036 toc31
-40
TA = -40°C
0.99
1.228
1.226
TA = +25°C
1.01
NORMALIZED VREF
VREF (V)
1.232
100k
FREQUENCY (Hz)
REFERENCE VOLTAGE
vs. TEMPERATURE
1.236
10k
1k
FREQUENCY (Hz)
MAX4036 toc29
10
0
-10
GAIN (dB)
45
20
PHASE (DEGREES)
90
40
30
MAX4036 toc26
70
60
50
GAIN (dB)
LARGE-SIGNAL GAIN
vs. FREQUENCY
MAX4036 toc25
80
VREF (V)
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
_______________________________________________________________________________________
400
500
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
REFERENCE LOAD-TRANSIENT RESPONSE
(SINKING CURRENT)
REFERENCE LOAD-TRANSIENT RESPONSE
(SINKING CURRENT)
MAX4036 toc33
MAX4036 toc32
0
IREF
0
IREF
2μA
20μA
VREF
500mV/div
VREF
500mV/div
0
0
2.5ms/div
2.5ms/div
REFERENCE LOAD-TRANSIENT RESPONSE
(SOURCING CURRENT)
REFERENCE LOAD-TRANSIENT RESPONSE
(SOURCING CURRENT)
MAX4036 toc34
MAX4036 toc35
10μA
100μA
IREF
0
IREF
0
VREF
500mV/div
VREF
500mV/div
0
0
1ms/div
1ms/div
REFERENCE TURN-ON
TRANSIENT RESPONSE
0.1Hz TO 10Hz REFERENCE NOISE
MAX4036 toc37
MAX4036 toc36
3V
VDD
0V
VREF
0V
1ms/div
1s/div
20μV/div
_______________________________________________________________________________________
9
MAX4036–MAX4039
Typical Operating Characteristics (continued)
(VDD = 3V, VSS = VCM = 0V, RL to 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
PIN
MAX4038/
MAX4039
MAX4036/
MAX4038A
MAX4037
MAX4036A
µMAX*/TDFN UCSP µMAX/TDF
UCSP
1
3
—
—
2
3
2
4
4
—
4
1
NAME
FUNCTION
—
—
IN+
Noninverting Amplifier Input
A2
5
A2
VSS
Negative Power-Supply Voltage
—
—
—
IN-
—
—
—
—
OUT
Amplifier Output
Positive Power-Supply Voltage
Inverting Amplifier Input
5
6
8
C2
10
C2
VDD
—
5
—
—
6
B2
REF
—
—
1
C1
1
C1
OUTA
—
—
2
B1
2
B1
INA-
Inverting Amplifier Input (Channel A)
—
—
3
A1
3
A1
INA+
Noninverting Amplifier Input (Channel A)
—
—
5
A3
7
A3
INB+
Noninverting Amplifier Input (Channel B)
—
—
6
B3
8
B3
INB-
Inverting Amplifier Input (Channel B)
—
—
7
C3
9
C3
OUTB
—
—
—
B2
4
—
N.C.
—
—
—
—
—
—
EP
(TDFN only)
Reference Voltage Output
Amplifier Output (Channel A)
Amplifier Output (Channel B)
No Connection. Not internally connected.
Exposed Paddle. Solder EP to VSS or leave
unconnected (TDFN packages only).
*Both MAX4038/MAX4038A available in µMAX package only.
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 commonmode 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 lowvoltage, battery-powered systems.
AV = 1V/V
VIN_+
1.5V
VOUT+
1.5V
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 typically swings from 5mV to VDD - 5mV with a 100kΩ load.
10
2ms/div
1V/div
Figure 1. Rail-to-Rail Input/Output Voltage Range
______________________________________________________________________________________
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
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 decaying battery voltage, simplifying design and extending
battery life. The MAX4036–MAX4039 are ideally suited
for low-voltage battery-powered systems. The Typical
Operating Characteristics show 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 indeterminate. 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 RISO forms a voltagedivider 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
RISO
MAX4038
RL
CL
INPUT
VHB
VTHF
VOH
OUTPUT
VOL
Figure 3. Hysteresis
distortion as the output stage passes between sinking
and sourcing. In the crossover regions, the output
impedance of the MAX4036–MAX4039 increases substantially, thereby changing the load-driving characteristics. 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 batterymonitoring applications. Hysteresis can be set using
resistors as shown in Figure 4, and the following design
procedure:
1) 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. 10MΩ is a good practical value.
2)
AV =
VTHR
Choose the hysteresis voltage (VHB), the voltage
between the upper and lower thresholds. In this
example, choose VHB = 50mV (see Figure 3).
RL
=1
RL + RISO
Figure 2. Using a Resistor to Isolate a Capacitive Load from
the Op Amp
______________________________________________________________________________________
11
MAX4036–MAX4039
Applications Information
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
3)
Calculate R1:
VHB
VDD
0.5V
= 10MΩ ×
2.4 V
= 210kΩ
R3
R1 = R 3 ×
4)
5)
VBATT
IN+
Choose the threshold voltage for VIN rising (VTHR).
In this example, choose VTHR = 2.0V.
Calculate R2:
OUT
R2
⎡⎛ VTHR ⎞
1
1 ⎤
−
−
⎢⎜
⎥
⎟
R1
R 3 ⎥⎦
⎢⎣⎝ VREF × R1⎠
1
=
⎡⎛
2.0V
1
1 ⎤
⎞
−
⎟ −
⎢⎜
⎥
210kΩ
10MΩ ⎦
⎣⎝ 1.2V × 210kΩ ⎠
= 325kΩ
VSS
REF
VREF
Figure 4. Battery Monitoring
Selector Guide
PART
VIN falling:
⎛ R1 × VDD ⎞
VTHF = VTHR − ⎜
⎟
⎝
⎠
R3
In this application, the MAX4036–MAX4039 supply current will vary, depending on the output state of the
comparator.
MAX4037
VSS
Verify the threshold voltages with these formulas:
VIN rising:
1
1 ⎞
⎛ 1
VTHR = VREF × R1 × ⎜
+
+
⎟
⎝ R1
R2
R3 ⎠
VBGOOD
IN-
1
R2 =
6)
VDD
VDD
R1
NO. OF AMPLIFIERS
REFERENCE
MAX4036
1
—
MAX4037
1
√
MAX4038
2
—
MAX4039
2
√
Ordering Information (continued)
PART
TEMP RANGE
PINPACKAGE
TOP
MARK
Power Supplies and Layout
MAX4039EBL-T
-40°C to +85°C
9 UCSP
AEH
The MAX4036–MAX4039 operate from a single 1.4V
(MAX4036/MAX4038) or 1.8V (MAX4037/MAX4039) to
3.6V power supply. Bypass VDD with a 0.1µF capacitor
to ground to minimize noise.
Good layout techniques optimize performance by
decreasing the amount of stray capacitance to the op
amp’s inputs and outputs. To decrease stray capacitance, minimize trace lengths by placing external components close to the device.
MAX4039ETB-T
-40°C to +85°C
10 TDFN-EP*
AAN
MAX4039EUB
-40°C to +85°C
10 µMAX
The exposed paddle (EP) on the TDFN packages of the
MAX4038 and MAX4039 is internally connected to the
device substrate, VSS. Connect the exposed paddle to
VSS or leave EP unconnected. Running traces below the
exposed paddle is not recommended.
12
—
-Denotes a package containing lead.
*EP = Exposed pad.
Chip Information
MAX4036 TRANSISTOR COUNT: 49
MAX4037 TRANSISTOR COUNT: 119
MAX4038 TRANSISTOR COUNT: 146
MAX4039 TRANSISTOR COUNT: 146
PROCESS: BiCMOS
______________________________________________________________________________________
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
TOP VIEW
5 VDD
IN+ 1
VSS 2
OUT 1
MAX4036
MAX4036A
6 VDD
MAX4037
VSS 2
4 OUT
IN- 3
4 IN-
IN+ 3
SC70
SOT23
8 VDD
OUTA 1
INA- 2
MAX4038
MAX4038A
INA+ 3
5 REF
VSS 4
OUTA 1
7 OUTB
INA- 2
6 INB-
INA+ 3
5 INB+
VSS 4
μMAX
8 VDD
7 OUTB
MAX4038
6 INB5 INB+
3mm x 3mm x 0.8mm TDFN
TDFN EXPOSED PAD CONNECTED TO VSS.
OUTA 1
10 VDD
OUTA 1
10 VDD
9 OUTB
INA- 2
8 INB-
INA+ 3
4
7 INB+
N.C. 4
7 INB+
5
6 REF
VSS 5
6 REF
INA-
2
INA+
3
N.C.
VSS
MAX4039
μMAX
9 OUTB
8 INB-
MAX4039
3mm x 3mm x 0.8mm TDFN
TDFN EXPOSED PAD CONNECTED TO VSS.
MAX4038
MAX4039
(BUMP SIDE DOWN)
(BUMP SIDE DOWN)
A
INA+
VSS
INB+
A
INA+
VSS
INB+
B
INA-
N.C.
INB-
B
INA-
REF
INB-
C
OUTA
VDD
OUTB
C
OUTA
VDD
OUTB
2
3
2
3
1
UCSP
1
UCSP
______________________________________________________________________________________
13
MAX4036–MAX4039
Pin Configurations
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
SC70, 5L.EPS
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
PACKAGE OUTLINE, 5L SC70
21-0076
14
______________________________________________________________________________________
E
1
1
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
6LSOT.EPS
PACKAGE OUTLINE, SOT 6L BODY
21-0058
I
1
2
______________________________________________________________________________________
15
MAX4036–MAX4039
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
PACKAGE OUTLINE, SOT 6L BODY
21-0058
16
______________________________________________________________________________________
I
2
2
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
α
α
______________________________________________________________________________________
17
MAX4036–MAX4039
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
18
______________________________________________________________________________________
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
COMMON DIMENSIONS
PACKAGE VARIATIONS
MIN.
MAX.
PKG. CODE
N
D2
E2
e
JEDEC SPEC
b
A
0.70
0.80
T633-2
6
1.50±0.10
2.30±0.10
0.95 BSC
MO229 / WEEA
0.40±0.05
1.90 REF
D
2.90
3.10
T833-2
8
1.50±0.10
2.30±0.10
0.65 BSC
MO229 / WEEC
0.30±0.05
1.95 REF
E
2.90
3.10
T833-3
8
1.50±0.10
2.30±0.10
0.65 BSC
MO229 / WEEC
0.30±0.05
1.95 REF
0.05
T1033-1
10
1.50±0.10
2.30±0.10
0.50 BSC
MO229 / WEED-3
0.25±0.05
2.00 REF
0.40
T1033MK-1
10
1.50±0.10
2.30±0.10
0.50 BSC
MO229 / WEED-3
0.25±0.05
2.00 REF
0.25 MIN.
T1033-2
10
1.50±0.10
2.30±0.10
0.50 BSC
MO229 / WEED-3
0.25±0.05
2.00 REF
0.20 REF.
T1433-1
14
1.70±0.10
2.30±0.10
0.40 BSC
----
0.20±0.05
2.40 REF
T1433-2
14
1.70±0.10
2.30±0.10
0.40 BSC
----
0.20±0.05
2.40 REF
T1433-3F
14
1.70±0.10
2.30±0.10
0.40 BSC
----
0.20±0.05
2.40 REF
SYMBOL
A1
L
k
A2
0.00
0.20
[(N/2)-1] x e
______________________________________________________________________________________
19
MAX4036–MAX4039
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
10LUMAX.EPS
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
α
α
20
______________________________________________________________________________________
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
9LUCSP, 3x3.EPS
PACKAGE OUTLINE, 3x3 UCSP
21-0093
L
1
1
______________________________________________________________________________________
21
MAX4036–MAX4039
Package Information (continued)
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the
package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the
package regardless of RoHS status.
MAX4036–MAX4039
Low IBIAS, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
Revision History
REVISION
NUMBER
REVISION
DATE
5
11/09
DESCRIPTION
Updated TOC 20
PAGES
CHANGED
7
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.
22 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2009 Maxim Integrated Products
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