General Description

The MAX4236/MAX4237 are high-precision op amps that feature an exceptionally low offset voltage and offset voltage temperature coefficient without using any chopper techniques. The MAX4236 and MAX4237 have a typical large-signal, open-loop voltage gain of 120dB. These devices have an ultra-low input-bias current of 1pA. The MAX4236 is unity-gain stable with a gain bandwidth product of 1.7MHz, while the MAX4237 is stable for closed-loop gains greater than 5V/V with a gain-bandwidth product of 7.5MHz. Both devices have a shutdown function in which the quiescent current is reduced to less than 0.1µA, and the amplifier output is forced into a high-impedance state.

The input common-mode range of the MAX4236/MAX4237 extends below the negative supply range, and the output swings Rail-to-Rail®. These features make the amplifiers ideal for applications with +3V or +5V single power supplies. The MAX4236/MAX4237 are specified for the extended temperature range (-40°C to +85°C) and are available in tiny SOT23, µMAX, and SO packages. For greater accuracy, the A grade µMAX and SO packages are tested to guarantee 20µV (max) offset voltage at +25°C and less then 2µV/°C drift.

Features

♦ Ultra-Low Offset Voltage

20µV (max) at +25°C (Grade A)

50µV (max) at +25°C (Grade B, 6-Pin SOT23)

♦ Ultra-Low Offset Voltage Drift

2µV/°C (max) (Grade A)

4.5µV/°C (max) (Grade B, 6-Pin SOT23)

5.5µV/°C (max) (6-Pin SOT23)

♦ Ultra-Low 1pA Input Bias Current

♦ High Open-Loop Voltage Gain: 110dB (min)

(RL = 100kΩ)

♦ Compatible with +3V and +5V Single-Supply

Power Systems

♦ Ground Sensing: Input Common-Mode Range

Includes Negative Rail

♦ Rail-to-Rail Output Swing into a 1kΩ Load

♦ 350µA Quiescent Current

♦ Gain-Bandwidth Product

1.7MHz (MAX4236, AV = 1V/V)

7.5MHz (MAX4237, AV = 5V/V)

♦ 200pF Capacitive Load Handling Capability

♦ Shutdown Mode: 0.1µA Quiescent Current,

Places Output in a High-Impedance State

♦ Available in Space-Saving SOT23 and µMAX Packages

Applications

Strain Gauges

Piezoelectric Sensors

Thermocouple Amplifiers

Electrochemical Sensors

Battery-Powered Instrumentation

Instrumentation Amplifiers