MAXIM MAX4036, MAX4039 Technical data

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 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.

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

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

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

________________________________________________________________

Maxim Integrated Products

1

Typical Operating Circuit

Ordering Information

MAX4039

OUTA

REF

INA-

INA+

V

SS

OUTB

INB-

INB+

V

DD

REF

Functional Diagram

19-3142; Rev 5; 11/09

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.

+

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.

Pin Configurations and Selector Guide appear at end of
data sheet.

PART TEMP RANGE

MAX4036EXK-T -40°C to +85°C 5 SC70 AFR

MAX4036AAXK+T -40°C to +125°C 5 SC70 ASN

MAX4037EUT-T -40°C to +85°C 6 SOT23 ABRX

MAX4038ETA-T -40°C to +85°C 8 TDFN-EP* AGO

MAX4038EUA -40°C to +85°C 8 µMAX —

MAX4038EBL-T -40°C to +85°C 9 UCSP AEG

MAX4038AAUA -40°C to +125°C 8 µMAX —

PIN­PACKAGE

TOP

MARK

3V

V

DD

INA-

OUTA

INA+

MAX4039

REF

INB+

V

THREE-ELECTRODE POTENTIOSTAT APPLICATION

INB-

OUTB

SS

SENSOR

ADC

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= +3V, VSS= VCM= 0V, V

OUT_

= 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 .........................(V

SS

- 0.3V) to (VDD+ 0.3V)

OUTA, OUTB, OUT, REF Shorted to V

SS

or VDD.......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

Supply Voltage Range V

Supply Current I

OPERATIONAL AMPLIFIERS

Input Offset Voltage V

Input Bias Current I

Input Offset Current I

Input Common-Mode Voltage
Range

Common-Mode Rejection Ratio CMRR

Power-Supply Rejection Ratio PSRR

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX4036/MAX4038, guaranteed by PSRR
tests

DD

MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests

MAX4036

MAX4037

DD

MAX4038

MAX4039

OS

(Note 1) ±1.0 ±10 pA

B

OS

V

(Note 1) ±0.3 ±20 pA

Guaranteed by

CM

CMRR test

VDD = 1.4V, VSS ≤ VCM ≤ (VDD - 0.4V)
(MAX4036/MAX4038 only)

VDD = 1.8V, VSS ≤ VCM ≤ (VDD - 0.3V) 50 70

= 3.3V, VSS ≤ VCM ≤ (VDD - 0.2V) 56 76

V

DD

1.4V ≤ VDD ≤ 3.6V (MAX4036/MAX4038
only)

1.8V ≤ V

≤ 3.6V 62 84

DD

1.4 3.6

1.8 3.6

VDD = 1.4V 0.8 1.2

= 3.6V 0.9 1.3

V

DD

VDD = 1.8V 1.9 2.4

= 3.6V 2.0 2.5

V

DD

VDD = 1.4V 1.7 2.3

= 3.6V 1.9 2.5

V

DD

VDD = 1.8V 2.8 4.0

V

= 3.6V 3.0 4.1

DD

±0.2 ±2.0 mV

V

= 1.4V

D D

( M AX 4036/M AX 4038 onl y)

VDD = 1.8V V

= 3.3V V

V

DD

V

SS

SS

SS

50 70

62 82

VDD -

0.4

VDD -

0.3

VDD -

0.2

V

µA

V

dB

dB

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +3V, VSS= VCM= 0V, V

OUT_

= VDD/2, RLto VDD/2, CL= 15pF, TA= +25°C, unless otherwise specified.)

ELECTRICAL CHARACTERISTICS

(VDD= +3V, VSS= VCM= 0V, V

OUT_

= VDD/2, RLto VDD/2, CL= 15pF, TA= T

MIN

to T

MAX

, unless otherwise specified.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Large-Signal Voltage Gain A

Output Voltage Swing High VDD - V

Output Voltage Swing Low VOL - V

Output Short-Circuit Current I

Gain-Bandwidth Product GBW 4 kHz

Phase Margin θ

Slew Rate SR 4 V/ms

Power-On Time t

Input Noise-Voltage Density e

Capacitive-Load Stability C

REFERENCE (MAX4037/MAX4039)

Reference Voltage V

Line Regulation

Load Regulation

Reference Output Voltage Noise e

Output Short-Circuit Current I

Capacitive-Load Stability Range C

VOL

SCO

ON

LOAD

REF

ΔV

REF

ΔV

ΔV

REF

ΔI

LOAD -20µA ≤ I

SCR

LOAD

RL = 100kΩ, 50mV ≤ V

RL = 5kΩ, 150mV ≤ V

RL = 100kΩ 25

OH

RL = 5kΩ 25 50

RL = 100kΩ 25

SS

RL = 5kΩ 25 50

To VDD or V

M

(Note 3) 0.25 ms
f = 1kHz 500 nV/√Hz

n

A

VCL

/

VDD = +1.8V to +3.6V 0.3 %/V

DD

0 ≤ I

/

0.1Hz to 10Hz 60 µV

n

Short to V

Short to V

(Note 1) 0 250 pF

OUT

≤ (VDD - 150mV) 78 105

OUT

SS

= 1V/V, no sustained oscillations 5000 pF

≤ 100µA, sourcing 0.0015

LOAD

≤ 0, sinking 0.0075

LOAD

DD

SS

- 50mV) 80 108

≤ (V

DD

1.226 1.232 1.238 V

±13 mA

90 Degrees

0.25

1.9

dB

mV

mV

%/µA

P-P

mA

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage Range V

Supply Current I

DD

DD

MAX4036/MAX4038, guaranteed by PSRR
test

MAX4037/MAX4039, guaranteed by PSRR
and line regulation tests

MAX4036

MAX4036A

MAX4037

VDD = 1.4V 1.7

= 3.6V 1.8

V

DD

VDD = 1.4V 2.0

V

= 3.6V 2.1

DD

VDD = 1.8V 3.1

V

= 3.6V 3.2

DD

1.4 3.6

V

1.8 3.6

µA

ELECTRICAL CHARACTERISTICS (continued)

(VDD= +3V, VSS= VCM= 0V, V

OUT_

= VDD/2, RLto VDD/2, CL= 15pF, TA= T

MIN

to T

MAX

, unless otherwise specified.) (Note 2)

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.

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

4 _______________________________________________________________________________________

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Current I

OPERATIONAL AMPLIFIERS

Input Offset Voltage V

Input Offset Voltage Temperature
Coefficient

Input Bias Current I

Input Offset Current I

Input Common-Mode Voltage
Range

Common-Mode Rejection Ratio CMRR

Power-Supply Rejection Ratio PSRR

Large-Signal Voltage Gain A

Output Voltage Swing High V

Output Voltage Swing Low VOL - V

REFERENCE (MAX4037/MAX4039)

Reference Voltage Temperature
Coefficient

Line Regulation

Load Regulation

Capacitive-Load Stability Range C

MAX4038

TCV

V

DD

TCV

ΔV

ΔV

ΔV
ΔI

DD

OS

CM

VOL

LOAD

LOAD

MAX4038A

MAX4039

OS

OS

B

Guaranteed by
CMRR test

VDD = 1.4V, VSS ≤ VCM ≤ (VDD - 0.5V)
(MAX4036/MAX4038 only)

VDD = 1.8V, VSS ≤ VCM ≤ (VDD - 0.4V) 50

V

= 3.3V, VSS ≤ VCM ≤ (VDD - 0.3V) 52

DD

1.4V ≤ VDD ≤ 3.6V
(MAX4036/MAX4038 only)

1.8V ≤ V

RL = 100kΩ, 50mV ≤ V

RL = 5kΩ, 150mV ≤ V

RL = 100kΩ 10

- V

OH

RL = 5kΩ 100

RL = 100kΩ 10

SS

RL = 5kΩ 100

(Note 1)

REF

/

REF

VDD = 1.8V to 3.6V 0.6 %/V

DD

0 ≤ I

/

REF

-20µA ≤ I

(Note 1) 0 250 pF

≤ 3.6V 60

DD

MAX4037EUT-T, MAX4039ETB,
MAX4039EUB

MAX4039EBL-T 35 200

≤ 100µA, sourcing 0.003

LOAD

≤ 0, sinking 0.015

LOAD

VDD = 1.4V 2.9

V

= 3.6V 3.2

DD

VDD = 1.4V 3.4

V

= 3.6V 3.7

DD

VDD = 1.8V 5.2

V

= 3.6V 5.3

DD

VDD = 1.4V
(MAX4036/MAX4038 only)

VDD = 1.8V V

V

= 3.3V V

DD

OUT

OUT

≤ (VDD - 50mV) 75

≤ (VDD - 150mV) 73

V

44

60

µA

±8 mV

±1 µV/°C

±100 pA

±200 pA

SS

SS

SS

25 120

VDD -

0.4

VDD -

0.4

VDD -

0.2

V

dB

dB

dB

mV

mV

ppm/°C

%/µA

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

_______________________________________________________________________________________

5

Typical Operating Characteristics

(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)

MAX4036

SUPPLY CURRENT

vs. SUPPLY VOLTAGE AND TEMPERATURE

1.6

1.2

0.8

SUPPLY CURRENT (μA)

0.4

0

1.4 3.4

TA = +85°C

TA = -40°C

SUPPLY VOLTAGE (V)

TA = +25°C

3.02.62.21.8

MAX4039

SUPPLY CURRENT

vs. SUPPLY VOLTAGE AND TEMPERATURE

5

4

3

2

SUPPLY CURRENT (μA)

1

TA = +85°C

TA = -40°C

TA = +25°C

3.0

2.5

MAX4036 toc01

2.0

1.5

1.0

SUPPLY CURRENT (μA)

0.5

1.0

MAX4036 toc04

0.8

0.6

0.4

OFFSET VOLTAGE (mV)

0.2

vs. SUPPLY VOLTAGE AND TEMPERATURE

0

1.8 3.6

vs. COMMON-MODE VOLTAGE

VDD = 1.4V

MAX4037

SUPPLY CURRENT

TA = +85°C

TA = -40°C

SUPPLY VOLTAGE (V)

TA = +25°C

OFFSET VOLTAGE

VDD = 1.8V

VDD = 3.0V

MAX4038

vs. SUPPLY VOLTAGE AND TEMPERATURE

3.0

2.5

MAX4036 toc02

2.0

1.5

1.0

SUPPLY CURRENT (μA)

0.5

3.33.02.72.42.1

MAX4036 toc05

0

1.4 3.4

0.30

0.20

0.10

0

-0.10

OFFSET VOLTAGE (mV)

-0.20

SUPPLY CURRENT

TA = +85°C

TA = -40°C

SUPPLY VOLTAGE (V)

TA = +25°C

OFFSET VOLTAGE

vs. TEMPERATURE

MAX4036 toc03

3.02.62.21.8

MAX4036 toc06

0

1.8 3.6
SUPPLY VOLTAGE (V)

INPUT BIAS CURRENT

vs. TEMPERATURE

40

30

20

10

INPUT BIAS CURRENT (pA)

0

-10

-40 85

TEMPERATURE (°C)

VCM = 3V

VCM = 0V

0

3.33.02.72.42.1

03

COMMON-MODE VOLTAGE (V)

21

INPUT BIAS CURRENT

vs. COMMON-MODE VOLTAGE

40

MAX4036 toc07

30

TA = +85°C

20

INPUT BIAS CURRENT (pA)

10

TA = +25°C

603510-15

0

0 3.0

COMMON-MODE VOLTAGE (V)

2.52.01.51.00.5

MAX4036 toc08

-0.30

-40 85
TEMPERATURE (°C)

OP AMP POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

0

AV = 1V/V

-10

-20

-30

-40

-50

PSRR (dB)

-60

-70

-80

-90

-100
10

FREQUENCY (Hz)

603510-15

MAX4036 toc09

10k1k100

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

6 _______________________________________________________________________________________

)

)

E

Typical Operating Characteristics (continued)

(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)

OUTPUT VOLTAGE SWING HIGH

vs. TEMPERATURE

30

25

20

(mV)

OH

15

- V

DD

V

10

RL = 5kΩ

5

0

RL = 100kΩ

-40 85
TEMPERATURE (°C)

603510-15

MAX4036 toc10

(mV)

- V
V

AV

vs. OUTPUT SWING HIGH

140

(dB)

V

A

120

100

RL = 5kΩ

RL = 100kΩ

80

60

MAX4036 toc13

OUTPUT VOLTAGE SWING LOW

vs. TEMPERATURE

35

30

25

RL = 5kΩ

20

SS

15

OL

10

5

0

-40 85

RL = 100kΩ

TEMPERATURE (°C)

AV

vs. TEMPERATURE

140

120

(dB)

VOL

A

100

80

60

40

20

RL = 100kΩRL = 5kΩ

vs. OUTPUT SWING LOW

AV

140

MAX4036 toc11

120

100

(dB)

V

A

80

60

603510-15

40

0 500

RL = 5kΩ

MAX4036 toc12

RL = 100kΩ

400300100 200

VOL (mV)

CROSSTALK

vs. FREQUENCY

0

MAX4038/MAX4039

MAX4036 toc14

AV = 1V/V

-20

-40

-60

CROSSTALK (dB)

-80

MAX4036 toc15

RL = 5kΩ

RL = 100kΩ

40

0 500

VDD - VOH (mV)

400300100 200

TOTAL HARMONIC DISTORTION PLUS NOIS

vs. FREQUENCY

100

10

1

THD+N (%)

0.1

0.01

0.01

V
RL = 100kΩ TO V

0.1 10 100
FREQUENCY (kHz)

V

= 2.5V

OUT

RL = 5kΩ TO V

= 2.5V

OUT

1

AV = 1V/V
V

IN_

P-P

P-P

= VDD/2

MAX4036 toc16

SS

SS

0

-40 85
TEMPERATURE (°C

OP AMP STABILITY

vs. CAPACITIVE AND RESISTIVE LOADS

100,000

UNSTABLE
REGION

10,000

1000

CAPACITIVE LOAD (pF)

STABLE
REGION

100

10k 100k 1M

RESISTIVE LOAD (Ω)

603510-15

RL TO V

-100
0

0.1 10k 100k

OP AMP SINK CURRENT

vs. OUTPUT VOLTAGE

14

VID = -100mV

12

MAX4036 toc17

10

8

6

SINK CURRENT (mA)

4

SS

2

0

0 3.0

1k

FREQUENCY (Hz

VDD = 1.8V

V

(V)

OUT_

VDD = 3.0V

2.41.81.20.6

MAX4036 toc18

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

________________________________________________________________________________________

7

Typical Operating Characteristics (continued)

(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)

OP AMP SOURCE CURRENT

vs. OUTPUT VOLTAGE

18

16

14

12

10

8

6

SOURCE CURRENT (mA)

4

2

0

VDD = 3.0V

VDD = 1.8V

0 3.0

V

(V)

OUT_

OP AMP

SMALL-SIGNAL TRANSIENT RESPONSE

AV = 1V/V

2.55V

2.45V

2.55V

2.45V

C
RL = 1MΩ TO V

VID = +100mV

2.41.81.20.6

= 12pF TO V

L

INPUT VOLTAGE NOISE DENSITY

vs. FREQUENCY

3500

MAX4036 toc19

3000

2500

2000

1500

1000

INPUT VOLTAGE NOISE (nV/√Hz)

500

0

0.1 10k
FREQUENCY (Hz)

MAX4036 toc20

1k100101

OP AMP

SMALL-SIGNAL TRANSIENT RESPONSE

AV = 1V/V

= 250pF TO V

SS

MAX4036 toc21

SS

V

IN

V

OUT_

2.55V

+

2.45V

2.55V

2.45V

C

L

RL = 1MΩ TO V

SS

MAX4036 toc22

SS

VIN+

V

OUT_

40μs/div

LARGE-SIGNAL TRANSIENT RESPONSE

OP AMP

2.5V

1.5V

100μs/div

AV = 1V/V

= 12pF TO V

C

L

RL = 1MΩ TO V

TURN-ON TRANSIENT RESPONSE

SS

MAX4036 toc23

SS

VIN+

V

OUT_

500mV/div

OP AMP

100μs/div

AV = 1V/V

= 12pF TO GND

C

L

= 1MΩ TO GND

R

L

+ = VDD / 2

V

IN

3.0V

MAX4036 toc24

V

DD

0V

V

OUT_

50mV/div

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

8 _______________________________________________________________________________________

)

Typical Operating Characteristics (continued)

(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)

GAIN AND PHASE

vs. FREQUENCY

80

70

GAIN

60
50

40
30

20

PHASE

GAIN (dB)

10

0

-10

-20
AV = 1000V/V

-30

= 1mV

V

IN_

-40

1 10 100 1k 10k 100k

P-P

FREQUENCY (Hz)

REFERENCE VOLTAGE

vs. TEMPERATURE

MAX4036 toc27

(V)

V

REF

1.234

1.233

1.232

1.231

(V)

V

REF

1.236

1.234

1.232

1.230

1.228

MAX4037/MAX4039

MAX4036 toc25

180

135

90

45

0

PHASE (DEGREES)

-45

-90

-135

REFERENCE VOLTAGE CHANGE

vs. TIME

MAX4037

MAX4039

LARGE-SIGNAL GAIN

vs. FREQUENCY

2

-2

-6

-10

-14

GAIN (dB)

-18

-22

-26

-30

RL = 5kΩ

AV = 1

= 1V

V

OUT_

P-P

CL = 12pF

100 10k 100k

1k

FREQUENCY (Hz)

MAX4036 toc28

RL = 1MΩ

1.02

1.01

REF

1.00

NORMALIZED V

0.99

MAX4036 toc26

RL = 100kΩ

REFERENCE VOLTAGE CHANGE

vs. LOAD CURRENT

TA = +85°C

TA = +25°C

TA = -40°C

MAX4036 toc29

1.226

-40 85
TEMPERATURE (°C)

603510-15

1.230
0 600

TIME (HR)

500400300200100

0.98

-100 500
LOAD CURRENT (μA

REFERENCE VOLTAGE CHANGE

1.0003

vs. SUPPLY VOLTAGE

1.0002

1.0001

REF

1.0000

0.9999

0.9998

NORMALIZED V

0.9997

0.9996

0.9995

1.8 3.6

TA = +25°C

TA = +85°C

VDD (V)

MAX4036 toc30

TA = -40°C

AC-COUPLED

3.33.02.1 2.4 2.7

REFERENCE LINE-TRANSIENT RESPONSE

3.6V

V

DD

1.8V

0V

V

REF

50mV/div

1ms/div

4003002001000

MAX4036 toc31

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

_______________________________________________________________________________________

9

Typical Operating Characteristics (continued)

(VDD= 3V, VSS= VCM= 0V, RLto VDD/2, TA= +25°C, unless otherwise noted.)

REFERENCE LOAD-TRANSIENT RESPONSE

(SINKING CURRENT)

0

I

REF

2μA

V

REF

500mV/div

0

2.5ms/div

REFERENCE LOAD-TRANSIENT RESPONSE

(SOURCING CURRENT)

10μA

I

REF

0

MAX4036 toc32

MAX4036 toc34

REFERENCE LOAD-TRANSIENT RESPONSE

(SINKING CURRENT)

0

I

REF

20μA

V

REF

500mV/div

0

2.5ms/div

REFERENCE LOAD-TRANSIENT RESPONSE

(SOURCING CURRENT)

100μA

I

REF

0

MAX4036 toc33

MAX4036 toc35

V

500mV/div

REF

0

1ms/div

V

500mV/div

REF

0

1ms/div

REFERENCE TURN-ON

TRANSIENT RESPONSE

1ms/div

MAX4036 toc36

3V

V

DD

0V

V

REF

0V

0.1Hz TO 10Hz REFERENCE NOISE

1s/div

20μV/div

MAX4036 toc37

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

10 ______________________________________________________________________________________

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.

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.

Figure 1. Rail-to-Rail Input/Output Voltage Range

*

Both MAX4038/MAX4038A available in µMAX package only.

PIN

MAX4036/

MAX4036A

1 3 — — — — IN+ Noninverting Amplifier Input

2 2 4 A2 5 A2 V

3 4 — — — — IN- Inverting Amplifier Input

4 1 — — — — OUT Amplifier Output

56 8C210C2VDDPositive Power-Supply Voltage

— 5 — — 6 B2 REF Reference Voltage Output

— — 1 C1 1 C1 OUTA Amplifier Output (Channel A)

— — 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 Amplifier Output (Channel B)

— — — B2 4 — N.C. No Connection. Not internally connected.

—— ————

MAX4037

MAX4038/

MAX4038A

µMAX*/TDFN UCSP

MAX4039

µMAX/TDF

UCSP

NAME FUNCTION

SS

EP

(TDFN only)

Negative Power-Supply Voltage

Exposed Paddle. Solder EP to V
unconnected (TDFN packages only).

or leave

SS

AV = 1V/V

V

IN_+

V

OUT+

2ms/div

1V/div

1.5V

1.5V

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

______________________________________________________________________________________ 11

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 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 R

ISO

forms 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 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 V

REF

/ R3, or 100nA

for R3 = 12MΩ. 10MΩ is a good practical value.

2) Choose the hysteresis voltage (VHB), the voltage
between the upper and lower thresholds. In this
example, choose VHB= 50mV (see Figure 3).

Figure 2. Using a Resistor to Isolate a Capacitive Load from
the Op Amp

Figure 3. Hysteresis

R

ISO

MAX4038

R

L

R

L

AV = = 1

RL + R

ISO

C

L

V

THR

INPUT

V

THF

OUTPUT

V

HB

V

OH

V

OL

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

12 ______________________________________________________________________________________

3) Calculate R1:

4) Choose the threshold voltage for V

IN

rising (V

THR

).

In this example, choose V

THR

= 2.0V.

5) Calculate R2:

6) Verify the threshold voltages with these formulas:

V

IN

rising:

VINfalling:

In this application, the MAX4036–MAX4039 supply cur­rent will vary, depending on the output state of the
comparator.

Power Supplies and Layout

The MAX4036–MAX4039 operate from a single 1.4V
(MAX4036/MAX4038) or 1.8V (MAX4037/MAX4039) to

3.6V power supply. Bypass VDDwith 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.

The exposed paddle (EP) on the TDFN packages of the
MAX4038 and MAX4039 is internally connected to the
device substrate, V

SS

. Connect the exposed paddle to

V

SS

or leave EP unconnected. Running traces below the

exposed paddle is not recommended.

Chip Information

MAX4036 TRANSISTOR COUNT: 49

MAX4037 TRANSISTOR COUNT: 119

MAX4038 TRANSISTOR COUNT: 146

MAX4039 TRANSISTOR COUNT: 146

PROCESS: BiCMOS

Figure 4. Battery Monitoring

Selector Guide

Ordering Information (continued)

-

Denotes a package containing lead.

*

EP = Exposed pad.

V

M

Ω

k

Ω

HB

V

DD

05
24

.
.

V

V

RR

13

=×

10

=×

210

=

×

.

×

1

⎞

1

−−

⎟

1

1

⎠

⎤

1

⎥

3

⎥

⎦

1

V

⎞
⎟

⎠

ΩΩΩ

1

−−

210

10

R

2

=

⎡

⎛

V

THR

⎢

⎜

VRRR

⎝

⎢

REF

⎣

=

⎡

=

⎢
⎣

325

20

⎛
⎜

⎝

Vk k M

1 2 210

.

k

Ω

1

VVR

=××++

THR REF

⎛

1

⎜
⎝

RR R

1

1

2

1

RV

×

VV

=−

THF THR

⎛
⎜

⎝

⎞

DD

⎟
⎠

3

R

R3

V

V

BATT

⎤

1

R1

IN+

R2

IN-

REF

V

REF

DD

V

DD

OUT

V

SS

MAX4037

V

SS

V

BGOOD

⎥
⎦

PART NO. OF AMPLIFIERS REFERENCE

1

⎞
⎟

⎠

3

MAX4036 1 —
MAX4037 1 √

MAX4038 2 —
MAX4039 2 √

PART TEMP RANGE

MAX4039EBL-T -40°C to +85°C 9 UCSP AEH

MAX4039ETB-T -40°C to +85°C 10 TDFN-EP* AAN

MAX4039EUB -40°C to +85°C 10 µMAX —

PIN­PACKAGE

TOP

MARK

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

______________________________________________________________________________________ 13

Pin Configurations

TOP VIEW

OUTA

INA-

INA+

1

IN+

MAX4036

2

V

SS

IN-

MAX4036A

3

SC70

1

2

MAX4038

3

MAX4038A

4

SS

μMAX

5

V

DD

4

OUT

OUT

V

IN+

V

1

MAX4037

2

SS

3

6

DD

REF

5

IN-

4

SOT23

8

V

DD

OUTB

7

INB-

6

INB+V

5

OUTA

INA-

INA+

V

1

2

3

4

SS

MAX4038

8

V

DD

OUTB

7

INB-

6

INB+

5

3mm x 3mm x 0.8mm TDFN

TDFN EXPOSED PAD CONNECTED TO VSS.

(BUMP SIDE DOWN)

1

OUTA

2

INA-

MAX4039

3

INA+

4

V

5

SS

μMAX

MAX4038

A

INA+

B

C

123

V

SS

V

DD

UCSP

INB+

INB-INA- N.C.

OUTBOUTA

OUTA

INA-

INA+

N.C.

V

1

2

3

4

5

SS

MAX4039

10

V

DD

9

OUTB

8

INB-

7

INB+N.C.

6

REF

10

V

DD

OUTB

9

INB-

8

INB+

7

REF

6

3mm x 3mm x 0.8mm TDFN

TDFN EXPOSED PAD CONNECTED TO V

.

SS

MAX4039

(BUMP SIDE DOWN)

A

INA+

B

C

V

V

123

INB+

SS

INB-INA- REF

OUTBOUTA

DD

UCSP

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

14 ______________________________________________________________________________________

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

PACKAGE OUTLINE, 5L SC70

21-0076

1

E

1

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

______________________________________________________________________________________ 15

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.

6LSOT.EPS

PACKAGE OUTLINE, SOT 6L BODY

21-0058

1

I

2

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

16 ______________________________________________________________________________________

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

2

I

2

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

______________________________________________________________________________________ 17

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.

α

α

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

18 ______________________________________________________________________________________

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 I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

______________________________________________________________________________________ 19

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.

COMMON DIMENSIONS

SYMBOL

MIN. MAX.

A 0.70 0.80

D 2.90 3.10

E 2.90 3.10

A1

0.00 0.05

L0.200.40

0.25 MIN.k

A2 0.20 REF.

PACKAGE VARIATIONS

PKG. CODE

T633-2

T833-2

T833-3

T1033-1

T1033MK-1

T1033-2

T1433-1

N D2

6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF

8 1.50±0.10 2.30±0.10

8 1.50±0.10 2.30±0.10

1.50±0.10

1.70±0.10 2.30±0.1014

E2 e

2.30±0.1010

2.30±0.101.50±0.10

2.30±0.10 MO229 / WEED-3 2.00 REF0.25±0.050.50 BSC1.50±0.1010

JEDEC SPEC

0.65 BSC MO229 / WEEC

0.65 BSC MO229 / WEEC

0.50 BSC

0.50 BSC MO229 / WEED-3

0.40 BSC

0.40 BSC

0.40 BSC

MO229 / WEED-3

- - - -

- - - - 0.20±0.05 2.40 REFT1433-3F 14 2.30±0.101.70±0.10

b

[(N/2)-1] x e

0.30±0.05 1.95 REF

0.30±0.05 1.95 REF

2.00 REF0.25±0.05

0.25±0.05 2.00 REF10

2.40 REF0.20±0.05- - - -

0.20±0.05 2.40 REFT1433-2 14 2.30±0.101.70±0.10

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

20 ______________________________________________________________________________________

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.

α

10LUMAX.EPS

α

MAX4036–MAX4039

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

______________________________________________________________________________________ 21

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.

9LUCSP, 3x3.EPS

PACKAGE OUTLINE, 3x3 UCSP

1

21-0093

L

1

Low I

BIAS

, +1.4V/800nA, Rail-to-Rail Op Amps

with +1.2V Buffered Reference

Revision History

REVISION

NUMBER

5 11

REVISION

DATE

/09 Updated TOC 20 7

MAX4036–MAX4039

DESCRIPTION

PAGES

CHANGED

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

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© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.