19-3142; Rev 5; 11/09


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

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.

Features

MAX4036–MAX4039

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


PART

TEMP RANGE

PIN- PACKAGE

TOP MARK

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

+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


OUTA VDD

MAX4039


INA- OUTB


INB-

INA+ REF

INB+

REF


VSS

3V

INA-

VDD OUTA


INA+ MAX4039 SENSOR REF

INB-


INB+

OUTB 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

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

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS


Supply Voltage Range


VDD

MAX4036/MAX4038, guaranteed by PSRR tests

1.4


3.6


V

MAX4037/MAX4039, guaranteed by PSRR and line regulation tests

1.8


3.6


Supply Current


IDD

MAX4036

VDD = 1.4V


0.8

1.2


µA

VDD = 3.6V


0.9

1.3

MAX4037

VDD = 1.8V


1.9

2.4

VDD = 3.6V


2.0

2.5

MAX4038

VDD = 1.4V


1.7

2.3

VDD = 3.6V


1.9

2.5

MAX4039

VDD = 1.8V


2.8

4.0

VDD = 3.6V


3.0

4.1

OPERATIONAL AMPLIFIERS

Input Offset Voltage

VOS



±0.2

±2.0

mV

Input Bias Current

IB

(Note 1)


±1.0

±10

pA

Input Offset Current

IOS

(Note 1)


±0.3

±20

pA


Input Common-Mode Voltage Range


VCM


Guaranteed by CMRR test

VDD = 1.4V (MAX4036/MAX4038 only)

VSS


VDD - 0.4


V

VDD = 1.8V

VSS


VDD - 0.3

VDD = 3.3V

VSS


VDD - 0.2


Common-Mode Rejection Ratio


CMRR

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

50

70



dB

VDD = 1.8V, VSS VCM (VDD - 0.3V)

50

70


VDD = 3.3V, VSS VCM (VDD - 0.2V)

56

76



Power-Supply Rejection Ratio


PSRR

1.4V VDD 3.6V (MAX4036/MAX4038

only)

62

82



dB

1.8V VDD 3.6V

62

84



MAX4036–MAX4039

ELECTRICAL CHARACTERISTICS (continued)

(VDD = +3V, VSS = VCM = 0V, VOUT_ = VDD/2, RL to VDD/2, CL = 15pF, TA = +25°C, unless otherwise specified.)


PARAMETER

SYMBOL

CONDITIONS

MIN TYP MAX

UNITS

Large-Signal Voltage Gain

AVOL

RL = 100kΩ, 50mV VOUT (VDD - 50mV)

80 108

dB

RL = 5kΩ, 150mV VOUT (VDD - 150mV)

78 105

Output Voltage Swing High

VDD - VOH

RL = 100kΩ

2 5

mV

RL = 5kΩ

25 50

Output Voltage Swing Low

VOL - VSS

RL = 100kΩ

2 5

mV

RL = 5kΩ

25 50

Output Short-Circuit Current

ISCO

To VDD or VSS

±13

mA

Gain-Bandwidth Product

GBW


4

kHz

Phase Margin

M


90

Degrees

Slew Rate

SR


4

V/ms

Power-On Time

tON

(Note 3)

0.25

ms

Input Noise-Voltage Density

en

f = 1kHz

500

nV/√Hz

Capacitive-Load Stability

CLOAD

AVCL = 1V/V, no sustained oscillations

5000

pF

REFERENCE (MAX4037/MAX4039)

Reference Voltage

VREF


1.226 1.232 1.238

V

Line Regulation

ΔVREF/ ΔVDD

VDD = +1.8V to +3.6V

0.3

%/V

Load Regulation

ΔVREF/ ΔILOAD

0 ILOAD 100µA, sourcing

0.0015

%/µA

-20µA ILOAD 0, sinking

0.0075

Reference Output Voltage Noise

en

0.1Hz to 10Hz

60

µVP-P

Output Short-Circuit Current

ISCR

Short to VDD

0.25

mA

Short to VSS

1.9

Capacitive-Load Stability Range

CLOAD

(Note 1)

0 250

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

SYMBOL

CONDITIONS

MIN TYP MAX

UNITS


Supply Voltage Range


VDD

MAX4036/MAX4038, guaranteed by PSRR test

1.4 3.6


V

MAX4037/MAX4039, guaranteed by PSRR and line regulation tests

1.8 3.6


Supply Current


IDD

MAX4036

VDD = 1.4V

1.7


µA

VDD = 3.6V

1.8


MAX4036A

VDD = 1.4V

2.0

VDD = 3.6V

2.1


MAX4037

VDD = 1.8V

3.1

VDD = 3.6V

3.2


MAX4036–MAX4039

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

MIN TYP MAX

UNITS


µA


Supply Current


IDD


MAX4038

VDD = 1.4V

2.9

VDD = 3.6V

3.2


MAX4038A

VDD = 1.4V

3.4

VDD = 3.6V

3.7


MAX4039

VDD = 1.8V

5.2

VDD = 3.6V

5.3

OPERATIONAL AMPLIFIERS

Input Offset Voltage

VOS


±8

mV

Input Offset Voltage Temperature Coefficient

TCVOS


±1

µV/°C

Input Bias Current

IB


±100

pA

Input Offset Current

IOS


±200

pA


Input Common-Mode Voltage Range


VCM


Guaranteed by CMRR test

VDD = 1.4V (MAX4036/MAX4038 only)

VSS VDD -

0.4


V

VDD = 1.8V

VSS VDD -

0.4

VDD = 3.3V

VSS VDD -

0.2


Common-Mode Rejection Ratio


CMRR

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

44


dB

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

50

VDD = 3.3V, VSS VCM (VDD - 0.3V)

52


Power-Supply Rejection Ratio


PSRR

1.4V VDD 3.6V (MAX4036/MAX4038 only)

60


dB

1.8V VDD 3.6V

60


Large-Signal Voltage Gain


AVOL

RL = 100kΩ, 50mV VOUT (VDD - 50mV)

75


dB

RL = 5kΩ, 150mV VOUT (VDD - 150mV)

73

Output Voltage Swing High

VDD - VOH

RL = 100kΩ

10

mV

RL = 5kΩ

100

Output Voltage Swing Low

VOL - VSS

RL = 100kΩ

10

mV

RL = 5kΩ

100

REFERENCE (MAX4037/MAX4039)

Reference Voltage Temperature Coefficient


TCVREF


(Note 1)

MAX4037EUT-T, MAX4039ETB,

MAX4039EUB

25 120


ppm/°C

MAX4039EBL-T

35 200

Line Regulation

ΔVREF/ ΔVDD

VDD = 1.8V to 3.6V

0.6

%/V

Load Regulation

ΔVREF/ ΔILOAD

0 ILOAD 100µA, sourcing

0.003

%/µA

-20µA ILOAD 0, sinking

0.015

Capacitive-Load Stability Range

CLOAD

(Note 1)

0 250

pF

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.


MAX4036–MAX4039

Typical Operating Characteristics

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



1.6

MAX4036 SUPPLY CURRENT

MAX4036 toc01

vs. SUPPLY VOLTAGE AND TEMPERATURE


3.0

MAX4037 SUPPLY CURRENT

vs. SUPPLY VOLTAGE AND TEMPERATURE


3.0

MAX4038 SUPPLY CURRENT

vs. SUPPLY VOLTAGE AND TEMPERATURE


SUPPLY CURRENT (A)

1.2


TA = +85C


TA = +25C


2.5

TA = +85C

TA = +25C


MAX4036 toc02

SUPPLY CURRENT (A)

2.5


TA = +85C


MAX4036 toc03

TA = +25C

SUPPLY CURRENT (A)

2.0

2.0



0.8


0.4


TA = -40C

1.5


1.0


0.5


TA = -40C

1.5


1.0


0.5


TA = -40C


0

1.4


1.8


2.2


2.6


3.0


3.4

0

1.8


2.1


2.4


2.7


3.0


3.3


3.6

0

1.4


1.8


2.2


2.6


3.0


3.4

SUPPLY VOLTAGE (V)

MAX4039 SUPPLY CURRENT

vs. SUPPLY VOLTAGE AND TEMPERATURE

MAX4036 toc04







TA = +85C TA = +25C




















TA = -40C










5


4


1.0


0.8

SUPPLY VOLTAGE (V)


OFFSET VOLTAGE

vs. COMMON-MODE VOLTAGE


MAX4036 toc05

0.30


0.20

SUPPLY VOLTAGE (V)


MAX4036 toc06

OFFSET VOLTAGE vs. TEMPERATURE


SUPPLY CURRENT (A)

OFFSET VOLTAGE (mV)

3 0.6


2 0.4


1 0.2


VDD = 1.4V


VDD = 1.8V VDD = 3.0V


0.10


OFFSET VOLTAGE (mV)































0


-0.10


-0.20


0

1.8


2.1


2.4


2.7


3.0


3.3

0

3.6 0


1 2 3

-0.30


-40


-15 10 35


60 85


40


INPUT BIAS CURRENT (pA)

30


20


10


0


-10

SUPPLY VOLTAGE (V)


INPUT BIAS CURRENT vs. TEMPERATURE


VCM = 3V


VCM = 0V

COMMON-MODE VOLTAGE (V)


INPUT BIAS CURRENT

vs. COMMON-MODE VOLTAGE

MAX4036 toc07

40


INPUT BIAS CURRENT (pA)

30


TA = +85C

20


10

TA = +25C


0

TEMPERATURE (C)


OP AMP POWER-SUPPLY REJECTION RATIO vs. FREQUENCY

AV = 1V/V

MAX4036 toc08

MAX4036 toc09

0

-10

-20

-30

PSRR (dB)

-40

-50

-60

-70

-80

-90

-100

-40

-15 10 35

60 85

0 0.5

1.0

1.5

2.0

2.5

3.0

10 100 1k

10k

TEMPERATURE (C)

COMMON-MODE VOLTAGE (V)

FREQUENCY (Hz)


MAX4036–MAX4039

VDD - VOH (mV)

Typical Operating Characteristics (continued)

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



OUTPUT VOLTAGE SWING HIGH vs. TEMPERATURE






RL = 5kΩ





















RL = 100kΩ






30


25


20


15


10


5


0


OUTPUT VOLTAGE SWING LOW vs. TEMPERATURE

MAX4036 toc10

35


30


VOL - VSS (mV)

25 RL = 5kΩ 20

15


10


5

RL = 100kΩ

0


140


MAX4036 toc11

120


AV (dB)

100


80


60


40


AV

MAX4036 toc12

vs. OUTPUT SWING LOW


RL = 5kΩ


RL = 100kΩ

-40

-15 10 35 60 85

-40

-15 10 35 60 85

0 100 200

300

400

500

TEMPERATURE (C)

TEMPERATURE (C)

VOL (mV)



140


120

AV

vs. OUTPUT SWING HIGH


RL = 5kΩ


140


MAX4036 toc13

120


100

AV

vs. TEMPERATURE


MAX4036 toc14

0


-20

CROSSTALK vs. FREQUENCY

MAX4036 toc15

MAX4038/MAX4039 AV = 1V/V

AV (dB)

100


80


RL = 100kΩ

RL = 5kΩ

AVOL (dB)

80


60

RL = 100kΩ


CROSSTALK (dB)

-40


-60


R = 100k


RL = 5kΩ

L Ω

40

60 -80

20


40

0 100 200


300


400


500


0

-40


-15 10 35 60 85


-100


0 0.1 1k


10k 100k

VDD - VOH (mV)


TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY

MAX4036 toc16

100

AV = 1V/V

VIN_ = VDD/2


10


THD+N (%)

1


VOUT = 2.5VP-P RL = 5kΩ TO VSS


100,000


CAPACITIVE LOAD (pF)

10,000


1000

TEMPERATURE (C)


OP AMP STABILITY

vs. CAPACITIVE AND RESISTIVE LOADS


UNSTABLE REGION

FREQUENCY (Hz)


OP AMP SINK CURRENT vs. OUTPUT VOLTAGE

MAX4036 toc17

MAX4036 toc18

14

VID = -100mV

12 VDD = 3.0V


SINK CURRENT (mA)

10


8


6

VDD = 1.8V

4

0.1


0.01


VOUT = 2.5VP-P

RL = 100kΩ TO VSS


100


STABLE REGION

RL TO VSS 2

0

0.01 0.1 1

10 100

10k 100k 1M

0 0.6

1.2

1.8

2.4

3.0

FREQUENCY (kHz)

RESISTIVE LOAD (Ω)

VOUT_ (V)


MAX4036–MAX4039

Typical Operating Characteristics (continued)

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


OP AMP SOURCE CURRENT vs. OUTPUT VOLTAGE

18

16 VID = +100mV

VDD = 3.0V

SOURCE CURRENT (mA)

14

12

10

8

6 VDD = 1.8V

4

2


3500


MAX4036 toc19

INPUT VOLTAGE NOISE (nV/Hz)

3000


2500


2000


1500


1000


500


MAX4036 toc20

0

INPUT VOLTAGE NOISE DENSITY vs. FREQUENCY

0 0.1 1

10 100 1k

10k

0 0.6

1.2

1.8

2.4

3.0

FREQUENCY (Hz)

VOUT_ (V)


OP AMP

SMALL-SIGNAL TRANSIENT RESPONSE

OP AMP

MAX4036 toc21

MAX4036 toc22

SMALL-SIGNAL TRANSIENT RESPONSE


2.55V


2.45V


2.55V


2.45V


VIN+


AV = 1V/V

CL = 12pF TO VSS RL = 1MΩ TO VSS

VOUT_

2.55V


2.45V


2.55V


2.45V


VIN+


AV = 1V/V

CL = 250pF TO VSS RL = 1MΩ TO VSS

VOUT_


40s/div


OP AMP

LARGE-SIGNAL TRANSIENT RESPONSE

OP AMP

MAX4036 toc23

TURN-ON TRANSIENT RESPONSE


2.5V


1.5V


VIN+


AV = 1V/V

CL = 12pF TO VSS RL = 1MΩ TO VSS

VOUT_

500mV/div

3.0V VDD

AV = 1V/V

CL = 12pF TO GND RL = 1MΩ TO GND VIN+ = VDD / 2

MAX4036 toc24

0V


VOUT_

50mV/div


100s/div 100s/div


MAX4036–MAX4039

Typical Operating Characteristics (continued)

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



80

70 GAIN 60

50

40

GAIN (dB)

30

20

10 PHASE

GAIN AND PHASE vs. FREQUENCY


MAX4036 toc25


180


135


90


45


0


2


-2


PHASE (DEGREES)

-6


GAIN (dB)

-10

-14

LARGE-SIGNAL GAIN vs. FREQUENCY


MAX4036 toc26

RL = 1MΩ


R = 5k

0

-10

-20

-30

-40


AV = 1000V/V VIN_ = 1mVP-P


-45


-90


-135

-18


-22


-26


-30

L Ω


AV = 1

VOUT_ = 1VP-P CL = 12pF


RL = 100kΩ

1 10 100 1k 10k 100k

100 1k

10k 100k

FREQUENCY (Hz) FREQUENCY (Hz)



1.236


1.234


VREF (V)

1.232


1.230


1.228

REFERENCE VOLTAGE vs. TEMPERATURE


MAX4036 toc27



MAX4037/MAX4039
























1.234


1.233


VREF (V)

1.232


1.231

REFERENCE VOLTAGE CHANGE vs. TIME


MAX4037


MAX4039


1.02


MAX4036 toc28

NORMALIZED VREF

1.01


1.00


0.99

REFERENCE VOLTAGE CHANGE vs. LOAD CURRENT


MAX4036 toc29

TA = +85C TA = +25C TA = -40C


1.226


-40


-15 10 35 60 85

1.230

0


100


200


300


400


500


600

0.98


-100 0


100


200


300


400


500

TEMPERATURE (C)


REFERENCE VOLTAGE CHANGE vs. SUPPLY VOLTAGE

TIME (HR)

LOAD CURRENT (A)


REFERENCE LINE-TRANSIENT RESPONSE

1.0003


1.0002


NORMALIZED VREF

1.0001


1.0000


0.9999


0.9998


0.9997


0.9996


0.9995


TA = -40C TA = +25C

TA = +85C


3.6V VDD 1.8V


MAX4036 toc30

MAX4036 toc31

0V


VREF AC-COUPLED

50mV/div

1.8

2.1 2.4 2.7

VDD (V)

3.0

3.3

3.6

1ms/div


MAX4036–MAX4039

Typical Operating Characteristics (continued)

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


REFERENCE LOAD-TRANSIENT RESPONSE (SINKING CURRENT)

MAX4036 toc32

REFERENCE LOAD-TRANSIENT RESPONSE (SINKING CURRENT)

MAX4036 toc33


0

IREF

2A

0

IREF 20A


VREF

500mV/div

VREF

500mV/div



0 0


2.5ms/div 2.5ms/div


REFERENCE LOAD-TRANSIENT RESPONSE (SOURCING CURRENT)

MAX4036 toc34

REFERENCE LOAD-TRANSIENT RESPONSE (SOURCING CURRENT)

MAX4036 toc35


10A

IREF 0

100A

IREF 0



VREF

500mV/div

0


1ms/div


VREF

500mV/div

0


1ms/div


REFERENCE TURN-ON TRANSIENT RESPONSE


MAX4036 toc36


0.1Hz TO 10Hz REFERENCE NOISE

MAX4036 toc37


3V


VDD


0V


VREF 0V


1ms/div


1s/div 20V/div


PIN


NAME


FUNCTION

MAX4036/ MAX4036A


MAX4037

MAX4038/ MAX4038A

MAX4039

µMAX*/TDFN

UCSP

µMAX/TDF

UCSP

1

3

IN+

Noninverting Amplifier Input

2

2

4

A2

5

A2

VSS

Negative Power-Supply Voltage

3

4

IN-

Inverting Amplifier Input

4

1

OUT

Amplifier Output

5

6

8

C2

10

C2

VDD

Positive 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.

EP

(TDFN only)

Exposed Paddle. Solder EP to VSS or leave unconnected (TDFN packages only).

MAX4036–MAX4039

*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 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 100kΩ load.



AV = 1V/V


VIN_+ 1.5V


VOUT+ 1.5V


2ms/div 1V/div

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


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 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 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 RISO 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



RISO

MAX4038


RL CL


AV = RL = 1 RL + RISO

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



INPUT VTHR VHB

VTHF


VOH

OUTPUT

VOL

Figure 3. Hysteresis


MAX4036–MAX4039

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:

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


    MAX4036–MAX4039

  3. Calculate R1:


    R1


    R3


    VHB VDD

    10MΩ

    210kΩ

    0.5V

    2.4V

  4. Choose the threshold voltage for VIN rising (VTHR). In this example, choose VTHR = 2.0V.

  5. Calculate R2:

    R2 1

    V

    VTHR

    R1

    1 1

    R1 R3

    ⎢⎜

    REF

    1

    2.0V


    1 1

    1.2V

    325kΩ

    210kΩ⎠

    210kΩ

    10MΩ

    Figure 4. Battery Monitoring


    R3


    VDD

    R1 VDD

    VBATT

    IN+


    OUT V

    R2 BGOOD

    IN-


    REF VSS


    VREF MAX4037

    VSS

  6. Verify the threshold voltages with these formulas: VIN rising:

Selector Guide


V V

R1 1 1 1

PART

NO. OF AMPLIFIERS

REFERENCE

MAX4036

1

MAX4037

1

MAX4038

2

MAX4039

2

THR REF


VIN falling:

R1 R2 R3


V V

R1

VDD

THF THR

R3 Ordering Information (continued)

PART TEMP RANGE PIN- TOP

PACKAGE MARK

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 —

In this application, the MAX4036–MAX4039 supply cur- rent 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 VDD with a 0.1µF capacitor to ground to minimize noise.

Good layout techniques optimize performance by


-Denotes a package containing lead.

*EP = Exposed pad.

Chip Information

decreasing the amount of stray capacitance to the op amp’s inputs and outputs. To decrease stray capaci-

tance, minimize trace lengths by placing external com- ponents close to the device.

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.

MAX4036 TRANSISTOR COUNT: 49 MAX4037 TRANSISTOR COUNT: 119 MAX4038 TRANSISTOR COUNT: 146 MAX4039 TRANSISTOR COUNT: 146 PROCESS: BiCMOS


MAX4036–MAX4039

Pin Configurations


1

1

TOP VIEW


IN+


5


MAX4036 MAX4036A

VDD


OUT


5

2

6


MAX4037

VDD


2

VSS

VSS

REF


3

IN-

OUT

IN+

IN-


4

3

4

SC70 SOT23



6

3

OUTA 1


8 VDD


OUTA


8

1


MAX4038

VDD


INA- 2


INA+ 3


VSS 4


5

4

7

2

MAX4038 MAX4038A

7 OUTB


6 INB-


5 INB+

INA- INA+ VSS

OUTB INB- INB+

MAX

3mm x 3mm x 0.8mm TDFN

TDFN EXPOSED PAD CONNECTED TO VSS.



OUTA 1


INA- 2

INA+ 3

N.C. 4

VSS 5


MAX4039


10 VDD

9 OUTB


8 INB-


7 INB+


6 REF

OUTA INA- INA+ N.C. VSS

VDD OUTB


1 10


2 9

3 MAX4039 8

4 7

5

6


INB- INB+ REF

MAX

3mm x 3mm x 0.8mm TDFN

INB+

TDFN EXPOSED PAD CONNECTED TO VSS.



(BUMP SIDE DOWN)

A


B

MAX4038


INA+

VSS


INA-

N.C.


(BUMP SIDE DOWN)

A


B

MAX4039


INA+

VSS

INB+


INA-

REF

INB-



OUTB

VDD

OUTA

OUTB

VDD

OUTA

INB-

C C


1 2 3

UCSP

1 2 3

UCSP


MAX4036–MAX4039

Package Information

SC70, 5L.EPS

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, 5L SC70


21-0076

E

1

1


MAX4036–MAX4039

Package Information (continued)

6LSOT.EPS

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

I

1

2


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 OUTLINE, SOT 6L BODY


21-0058

I

2

2


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

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

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

L

0.20

0.40

k

0.25 MIN.

A2

0.20 REF.

PACKAGE VARIATIONS

PKG. CODE

N

D2

E2

e

JEDEC SPEC

b

[(N/2)-1] x e

T633-2

6

1.50±0.10

2.30±0.10

0.95 BSC

MO229 / WEEA

0.40±0.05

1.90 REF

T833-2

8

1.50±0.10

2.30±0.10

0.65 BSC

MO229 / WEEC

0.30±0.05

1.95 REF

T833-3

8

1.50±0.10

2.30±0.10

0.65 BSC

MO229 / WEEC

0.30±0.05

1.95 REF

T1033-1

10

1.50±0.10

2.30±0.10

0.50 BSC

MO229 / WEED-3

0.25±0.05

2.00 REF

T1033MK-1

10

1.50±0.10

2.30±0.10

0.50 BSC

MO229 / WEED-3

0.25±0.05

2.00 REF

T1033-2

10

1.50±0.10

2.30±0.10

0.50 BSC

MO229 / WEED-3

0.25±0.05

2.00 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


MAX4036–MAX4039

Package Information (continued)

10LUMAX.EPS

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

Package Information (continued)

9LUCSP, 3x3.EPS




























































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, 3x3 UCSP


21-0093

L

1

1


MAX4036–MAX4039

Revision History


REVISION NUMBER

REVISION DATE


DESCRIPTION

PAGES CHANGED

5

11/09

Updated TOC 20

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.

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

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