MAX5431AEUB+

Overview

The MAX5431AEUB+ is a digitally programmable precision resistor array designed for programmable-gain amplifier (PGA) applications. It provides four noninverting gain configurations of 1, 2, 4, and 8 with a ratio accuracy of 0.025%. The device operates from a single +15V or dual ±15V supply, consuming only 35µA of supply current. It features a CMOS/TTL logic compatible 2-wire parallel interface and includes an on-chip matching resistor for op amp input bias-current compensation. The component is housed in a space-saving 10-pin µMAX package and is specified over the extended temperature range of -40°C to +85°C.

Feature Summary

• Four Noninverting PGA Gain Configurations: AV = 1, 2, 4, and 8
• Precision 0.025% Ratio Accuracy
• On-Chip Matching Resistor for Op Amp Bias-Current Compensation
• Single-Supply +12V to +15V, or Dual-Supply ±12V to ±15V Operation

Applications

• General-Purpose Programmable Noninverting Amplifier
• Programmable Instrumentation Amplifier

Procurement Notes

Verify the specific ordering suffix 'U' corresponds to the 10-pin µMAX package and 'B' indicates the 0.09% accuracy grade if sourcing variants, though the primary model specifies 0.025% accuracy. Confirm the '+T' suffix denotes tape-and-reel packaging if applicable to the specific order code. Ensure compatibility with the required voltage range and temperature specifications for the target application environment.

Selection Notes

Select the MAX5431 variant when op amp input bias-current compensation is required, as it includes a dedicated matching resistor network not present in the MAX5430. Choose the 'A' suffix version for applications demanding the highest precision at 0.025% ratio accuracy. Ensure the design accommodates the 10-pin µMAX footprint and the low supply current requirements of 35µA typical.

Part Context

The MAX5431 is part of the MAX5430/MAX5431 family of digitally programmable high-precision resistor arrays. While the MAX5430 lacks the internal matching resistor, the MAX5431 integrates this feature specifically to compensate for offset voltages caused by op amp input bias currents. Both devices share identical gain settings and interface protocols but differ in their suitability for different op amp types based on bias current characteristics.

Replacement Considerations

The MAX5430AEUB+ serves as a direct functional substitute if the on-chip matching resistor is unnecessary and an ultra-low input bias current op amp is used instead. Verify that the replacement maintains the same 0.025% accuracy grade and 10-pin µMAX package form factor.

FAQ

What is the function of the MATCH_H and MATCH_L pins?

These pins connect to an on-chip matching resistor equal to the impedance seen at the W terminal for gains of 2, 4, and 8. This resistor compensates for offset voltage due to op amp input bias currents.

How is the gain setting controlled?

Gain is set via a simple two-bit parallel digital interface using inputs D0 and D1. The logic table defines gains of 1, 2, 4, and 8 for binary inputs 00, 01, 10, and 11 respectively.

What is the end-to-end resistance between H and L?

The resistance between the High (H) and Low (L) terminals is fixed at 57 kΩ.