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19-3142; Rev 4; 3/06
Low I
BIAS
, +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 V
DD
- 0.4V at V
DD
= 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.
Features
♦
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)
MAX4036–MAX4039
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
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.
Ordering Information
PART
MAX4036EXK-T
MAX4036AAXK+T
MAX4037EUT-T
MAX4038ETA-T
MAX4038EUA
MAX4038EBL-T
MAX4038AAUA
TEMP RANGE
-40°C to +85°C
-40°C to +125°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +125°C
PIN-
PACKAGE
5 SC70-5
5 SC70-5
6 SOT23-6
8 TDFN-EP*
8 µMAX
9 UCSP-9
8 µMAX
TOP
MARK
AFR
ASN
ABRX
AGO
—
AEG
—
+Denotes
lead-free package.
*EP
= Exposed paddle.
Ordering Information continued at end of data sheet.
Functional Diagram
3V
OUTA
Typical Operating Circuit
V
DD
INA-
OUTA
MAX4039
V
DD
INA-
OUTB
INB-
INA+
REF
INB+
REF
V
SS
INA+
REF
MAX4039
INB-
SENSOR
INB+
V
SS
OUTB
ADC
THREE-ELECTRODE POTENTIOSTAT APPLICATION
________________________________________________________________
Maxim Integrated Products
1
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.
Low I
BIAS
, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
MAX4036–MAX4039
ABSOLUTE MAXIMUM RATINGS
V
DD
to V
SS
.............................................................-0.3V to +4.0V
INA+, INB+, INA-, INB-, IN+, IN-, OUTA,
OUTB, OUT, REF .........................(V
SS
- 0.3V) to (V
DD
+ 0.3V)
OUTA, OUTB, OUT, REF Shorted to V
SS
or V
DD
.......Continuous
Maximum Continuous Power Dissipation (T
A
= +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
(V
DD
= +3V, V
SS
= V
CM
= 0V, V
OUT_
= V
DD
/2, R
L
to V
DD
/2, C
L
= 15pF,
T
A
= +25°C,
unless otherwise specified.)
PARAMETER
SYMBOL
CONDITIONS
MAX4036/MAX4038, guaranteed by PSRR
tests
Supply Voltage Range
V
DD
MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests
MAX4036
MAX4037
Supply Current
I
DD
MAX4038
MAX4039
OPERATIONAL AMPLIFIERS
Input Offset Voltage
Input Bias Current
Input Offset Current
V
OS
I
B
I
OS
(Note 1)
(Note 1)
V
DD
= 1.4V
(MAX4036/MAX4038 only)
Input Common-Mode Voltage
Range
V
CM
Guaranteed by
CMRR test
V
DD
=
1.8V
V
DD
= 3.3V
V
DD
= 1.4V, V
SS
≤
V
CM
≤
(V
DD
- 0.4V)
(MAX4036/MAX4038 only)
Common-Mode Rejection Ratio
CMRR
V
DD
= 1.8V, V
SS
≤
V
CM
≤
(V
DD
- 0.3V)
V
DD
= 3.3V, V
SS
≤
V
CM
≤
(V
DD
- 0.2V)
Power-Supply Rejection Ratio
PSRR
1.4V
≤
V
DD
≤
3.6V (MAX4036/MAX4038
only)
1.8V
≤
V
DD
≤
3.6V
V
SS
V
SS
V
SS
50
50
56
62
62
70
70
76
82
84
dB
dB
±0.2
±1.0
±0.3
±2.0
±10
±20
V
DD
-
0.4
V
DD
-
0.3
V
DD
-
0.2
V
mV
pA
pA
V
DD
= 1.4V
V
DD
= 3.6V
V
DD
= 1.8V
V
DD
= 3.6V
V
DD
= 1.4V
V
DD
= 3.6V
V
DD
= 1.8V
V
DD
= 3.6V
MIN
1.4
1.8
0.8
0.9
1.9
2.0
1.7
1.9
2.8
3.0
TYP
MAX
3.6
V
3.6
1.2
1.3
2.4
2.5
2.3
2.5
4.0
4.1
µA
UNITS
2
_______________________________________________________________________________________
Low I
BIAS
, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +3V, V
SS
= V
CM
= 0V, V
OUT_
= V
DD
/2, R
L
to V
DD
/2, C
L
= 15pF,
T
A
= +25°C,
unless otherwise specified.)
PARAMETER
Large-Signal Voltage Gain
Output Voltage Swing High
Output Voltage Swing Low
Output Short-Circuit Current
Gain-Bandwidth Product
Phase Margin
Slew Rate
Power-On Time
Input Noise-Voltage Density
Capacitive-Load Stability
REFERENCE (MAX4037/MAX4039)
Reference Voltage
Line Regulation
Load Regulation
Reference Output Voltage Noise
Output Short-Circuit Current
Capacitive-Load Stability Range
V
REF
∆V
REF
/
∆V
DD
∆V
REF
/
∆I
LOAD
e
n
I
SCR
C
LOAD
V
DD
= +1.8V to +3.6V
0
≤
I
LOAD
≤
100µA, sourcing
-20µA
≤
I
LOAD
≤
0, sinking
0.1Hz to 10Hz
Short to V
DD
Short to V
SS
(Note 1)
0
60
0.25
1.9
250
1.226
1.232
1.238
0.3
0.0015
0.0075
V
%/V
%/µA
µV
P-P
mA
pF
SYMBOL
A
VOL
V
DD
- V
OH
V
OL
- V
SS
I
SCO
GBW
θ
M
SR
t
ON
e
n
C
LOAD
(Note 3)
f = 1kHz
A
VCL
= 1V/V, no sustained oscillations
CONDITIONS
R
L
= 100kΩ, 50mV
≤
V
OUT
≤
(V
DD
- 50mV)
R
L
= 5kΩ, 150mV
≤
V
OUT
≤
(V
DD
- 150mV)
R
L
= 100kΩ
R
L
= 5kΩ
R
L
= 100kΩ
R
L
= 5kΩ
To V
DD
or V
SS
MIN
80
78
TYP
108
105
2
25
2
25
±13
4
90
4
0.25
500
5000
5
50
5
50
MAX
UNITS
dB
mV
mV
mA
kHz
Degrees
V/ms
ms
nV/√Hz
pF
MAX4036–MAX4039
ELECTRICAL CHARACTERISTICS
(V
DD
= +3V, V
SS
= V
CM
= 0V, V
OUT_
= V
DD
/2, R
L
to V
DD
/2, C
L
= 15pF,
T
A
= T
MIN
to T
MAX
, unless otherwise specified.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MAX4036/MAX4038, guaranteed by PSRR
test
Supply Voltage Range
V
DD
MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests
MAX4036
Supply Current
I
DD
MAX4036A
MAX4037
V
DD
= 1.4V
V
DD
= 3.6V
V
DD
= 1.4V
V
DD
= 3.6V
V
DD
= 1.8V
V
DD
= 3.6V
MIN
1.4
1.8
TYP
MAX
3.6
V
3.6
1.7
1.8
2.0
2.1
3.1
3.2
µA
UNITS
_______________________________________________________________________________________
3
Low I
BIAS
, +1.4V/800nA, Rail-to-Rail Op Amps
with +1.2V Buffered Reference
MAX4036–MAX4039
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +3V, V
SS
= V
CM
= 0V, V
OUT_
= V
DD
/2, R
L
to V
DD
/2, C
L
= 15pF,
T
A
= T
MIN
to T
MAX
, unless otherwise specified.) (Note 2)
PARAMETER
SYMBOL
MAX4038
CONDITIONS
V
DD
= 1.4V
V
DD
= 3.6V
Supply Current
I
DD
MAX4038A
V
DD
= 1.4V
V
DD
= 3.6V
MAX4039
OPERATIONAL AMPLIFIERS
Input Offset Voltage
Input Offset Voltage Temperature
Coefficient
Input Bias Current
Input Offset Current
V
OS
TCV
OS
I
B
I
OS
V
DD
= 1.4V
(MAX4036/MAX4038 only)
Input Common-Mode Voltage
Range
V
CM
Guaranteed by
CMRR test
V
DD
=
1.8V
V
DD
= 3.3V
V
DD
= 1.4V, V
SS
≤
V
CM
≤
(V
DD
- 0.5V)
(MAX4036/MAX4038 only)
Common-Mode Rejection Ratio
CMRR
V
DD
= 1.8V, V
SS
≤
V
CM
≤
(V
DD
- 0.4V)
V
DD
=
3.3V, V
SS
≤
V
CM
≤
(V
DD
- 0.3V)
1.4V
≤
V
DD
≤
3.6V
(MAX4036/MAX4038 only)
1.8V
≤
V
DD
≤
3.6V
Large-Signal Voltage Gain
A
VOL
R
L
= 100kΩ, 50mV
≤
V
OUT
≤
(V
DD
- 50mV)
R
L
= 5kΩ, 150mV
≤
V
OUT
≤
(V
DD
- 150mV)
R
L
= 100kΩ
R
L
= 5kΩ
R
L
= 100kΩ
R
L
= 5kΩ
MAX4037EUT-T, MAX4039ETB,
MAX4039EUB
MAX4039EBL-T
V
SS
V
SS
V
SS
44
50
52
60
60
75
73
10
100
10
100
mV
mV
dB
dB
dB
±1
±100
±200
V
DD
-
0.4
V
DD
-
0.4
V
DD
-
0.2
V
±8
mV
µV/°C
pA
pA
V
DD
= 1.8V
V
DD
= 3.6V
MIN
TYP
MAX
2.9
3.2
3.4
3.7
5.2
5.3
µA
UNITS
Power-Supply Rejection Ratio
PSRR
Output Voltage Swing High
Output Voltage Swing Low
V
DD
- V
OH
V
OL
- V
SS
REFERENCE (MAX4037/MAX4039)
Reference Voltage Temperature
Coefficient
Line Regulation
Load Regulation
Capacitive-Load Stability Range
TCV
REF
∆V
REF
/
∆V
DD
∆V
REF
/
∆I
LOAD
C
LOAD
(Note 1)
25
35
120
200
0.6
0.003
0.015
0
250
%/V
%/µA
pF
ppm/°C
V
DD
= 1.8V to 3.6V
0
≤
I
LOAD
≤
100µA, sourcing
-20µA
≤
I
LOAD
≤
0, sinking
(Note 1)
Note 1:
Guaranteed by design.
Note 2:
All devices are production tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Note 3:
Output settles within 1% of final value.
4
_______________________________________________________________________________________