MAXIM MAX4238, MAX4239 User Manual

General Description

The MAX4238/MAX4239 are low-noise, low-drift, ultra­high precision amplifiers that offer near-zero DC offset
and drift through the use of patented autocorrelating
zeroing techniques. This method constantly measures
and compensates the input offset, eliminating drift over
time and temperature and the effect of 1/f noise. Both
devices feature rail-to-rail outputs, operate from a single

2.7V to 5.5V supply, and consume only 600µA. An active­low shutdown mode decreases supply current to 0.1µA.

The MAX4238 is unity-gain stable with a gain-band­width product of 1MHz, while the decompensated
MAX4239 is stable with A

V

≥ 10V/V and a GBWP of

6.5MHz. The MAX4238/MAX4239 are available in 8-pin
narrow SO, 6-pin TDFN and SOT23 packages.

Applications

Thermocouples

Strain Gauges

Electronic Scales

Medical Instrumentation

Instrumentation Amplifiers

Features

o Ultra-Low, 0.1µV Offset Voltage

2.0µV (max) at +25°C

2.5µV (max) at -40°C to +85°C

3.5µV (max) at -40°C to +125°C

o Low 10nV/°C Drift

o Specified over the -40°C to +125°C Automotive

Temperature Range

o Low Noise: 1.5µV

P-P

from DC to 10Hz

o 150dB A

VOL

, 140dB PSRR, 140dB CMRR

o High Gain-Bandwidth Product

1MHz (MAX4238)

6.5MHz (MAX4239)

o 0.1µA Shutdown Mode

o Rail-to-Rail Output (R

L

= 1kΩ)

o Low 600µA Supply Current

o Ground-Sensing Input

o Single 2.7V to 5.5V Supply Voltage Range

o Available in a Space-Saving 6-Pin SOT23 and

TDFN Packages

MAX4238/MAX4239

Ultra-Low Offset/Drift, Low-Noise,

Precision SOT23 Amplifiers

________________________________________________________________

Maxim Integrated Products

1

Typical Application Circuit

19-2424; Rev 3; 8/11

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.

Pin Configurations appear at end of data sheet.

Note: All devices are specified over the -40°C to +125°C oper-

ating temperature range.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed paddle.

/V denotes an automotive-qualified part.

Ordering Information

Selector Guide

5V

18kΩ

18kΩ

AV = 100

MAX4238/

ADC

AIN

MAX4239

360Ω

STRAIN GAUGE

PART PIN-PACKAGE TOP MARK

MAX4238AUT-T 6 SOT23 AAZZ

MAX4238AUT/V+T 6 SOT23 —

MAX4238ASA 8 SO —

MAX4238ATT+T 6 TDFN-EP* +ANG

MAX4239AUT-T 6 SOT23 ABAA

MAX4239AUT/V+T 6 SOT23 —

MAX4239ASA 8 SO —

MAX4239ATT+T 6 TDFN-EP* +ANH

PART

MAX4238 1V/V 1
MAX4239 10V/V 6.5

MINIMUM STABLE

GAIN

GAIN

BANDWIDTH

(MHz)

MAX4238/MAX4239

Ultra-Low Offset/Drift, Low-Noise,
Precision SOT23 Amplifiers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(2.7V ≤ VCC≤ 5.5V, VCM= V

GND

= 0V, V

OUT

= VCC/2, RL= 10kΩ connected to VCC/2, SHDN = VCC, TA= +25°C,

unless otherwise noted.)

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.

Power-Supply Voltage (VCCto GND).......................................6V

All Other Pins ................................(V

GND

- 0.3V) to (VCC+ 0.3V)

Output Short-Circuit Duration

(OUT shorted to V

CC

or GND) ...............................Continuous

Continuous Power Dissipation (T

A

= +70°C)

6-Pin Plastic SOT23

(derate 9.1mW/°C above +70°C)...............................727mW

8-Pin Plastic SO (derate 5.88mW/°C above +70°C) ....471mW

6-Pin TDFN-EP (derate 18.2mW above +70°C) .........1454mW

Operating Temperature Range .........................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Soldering Temperature (reflow)

Lead(Pb)-Free Packages.............................................+260°C

Packages Containing Lead..........................................+240°C

Input Offset Voltage VOS (Note 1) 0.1 2 µV

Long-Term Offset Drift 50 nV/1000hr

Input Bias Current IB (Note 2) 1 pA

Input Offset Current IOS (Note 2) 2 pA

Peak-to-Peak Input Noise
Voltage

Input Voltage-Noise Density en f = 1kHz 30 NV/Hz

Common-Mode Input
Voltage Range

Common-Mode Rejection Ratio CMRR -0.1V  VCM VCC - 1.3V (Note 1) 120 140 dB

Power-Supply Rejection Ratio PSRR 2.7V  VCC 5.5V (Note 1) 120 140 dB

Large-Signal Voltage Gain A

Output Voltage Swing VOH/V

Output Short-Circuit Current To either suppl y 40 mA

Output Leakage Current 0  V

Slew Rate

Gain- Bandwidth Product GBWP

Min imum Stable Clo sed-Loop
Gain

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

e

RS = 100, 0.01Hz to 10Hz 1.5 µV

nP-P

Inferred from CMRR test

V

CM

VOL

OL

0.05V  V
(Note 1)

0.1V  V
(Note 1)

RL = 10k

RL = 1k

V
V

R
measured at f = 100kHz

RL = 10k, CL = 100pF,
phase margin = 60°

OUT

OUT

 VCC, SHDN = GND (Note 2) 0.01 1 µA

OUT

= 5V, CL = 100pF,

CC

= 2V step

OUT

= 10k, CL = 100pF,

L

V

CC

- 1.3

 VCC - 0.05V

 VCC - 0.1V

V

GND

- 0.1

= 10k 125 150

R

L

= 1k 125 145

R

L

VCC - VOH 4 10

4 10

V

OL

VCC - VOH 35 50

35 50

V

OL

MAX4238 0.35

MAX4239 1.6

MAX4238 1

MAX4239 6.5

MAX4238 1

MAX4239 10

P-P

V

dB

mV

V/µs

MHz

V/V

MAX4238/MAX4239

Ultra-Low Offset/Drift, Low-Noise,

Precision SOT23 Amplifiers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(2.7V ≤ VCC≤ 5.5V, VCM= V

GND

= 0V, V

OUT

= VCC/2, RL= 10kΩ connected to VCC/2, SHDN = VCC, TA= +25°C,

unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Max imum Closed-Loop Gain

Settling Time -1V step

Overload Reco ver y Time

Startup Time AV = 10

Supply Voltage Range VCC Inferred by PSRR test 2.7 5.5 V

Supply Current I

Shutdown Logic-High VIH 2.2 V

Shutdown Logic-Low VIL 0.8 V

Shutdown Input Current 0V  V

CC

= 10k, CL = 100pF,

R

L

phase margin = 60°

A

= 10

V

(Note 4)

SHDN = VCC, no load, VCC = 5.5V 600 850
SHDN = GND, VCC = 5.5V 0.1 1

 VCC 0.1 1 µA

SHDN

MAX4238 1000

MAX4239 6700

0.1% (10 bit) 0.5

0.025% (12 bit) 1.0

0.006% (14 bit) 1.7

0.0015% (16 bit) 2.3

0.1% (10 bit) 3.3

0.025% (12 bit) 4.1

0.006% (14 bit) 4.9

0.0015% (16 bit) 5.7

0.1% (10 bit) 1.8

0.025% (12 bit) 2.6

0.006% (14 bit) 3.4

0.0015% (16 bit) 4.3

V/V

ms

ms

ms

µA