ADR431AR

Overview

The ADR431AR is a series precision voltage reference from the ADR43x family, utilizing Analog Devices' patented XFET technology to minimize temperature drift nonlinearity. It provides a fixed 2.5 V output with an initial accuracy of ±0.12% for the A Grade and ±0.04% for the B Grade. The device operates within a supply voltage range of 4.5 V to 18 V and features low quiescent current consumption of 800 µA maximum. It offers high output source current capability of +30 mA and sink current of −20 mA. The unit includes a trim terminal for adjusting the output voltage over a 0.5% range without compromising performance.

Feature Summary

• Utilizes XFET technology with patented temperature drift curvature correction to minimize voltage change versus temperature nonlinearity.
• Features ultralow noise performance of 3.5 µV p-p in the 0.1 Hz to 10.0 Hz frequency band.
• Provides bidirectional current drive capability, sourcing up to 30 mA and sinking up to 20 mA.
• Includes an onboard trim terminal allowing output voltage adjustment over a 0.5% range.

Applications

• Precision data acquisition systems
• High resolution data converters
• Medical instruments
• Industrial process control systems

Procurement Notes

Verify the specific grade suffix (A or B) required for your application's accuracy and temperature coefficient specifications. Confirm the package type (MSOP or SOIC) matches your PCB footprint design. Ensure the input voltage headroom meets the minimum requirement of 2 V above the output voltage for proper regulation.

Selection Notes

Select the ADR431AR variant based on the required initial accuracy and temperature coefficient. The A Grade offers ±0.12% accuracy and 10 ppm/°C max drift, while the B Grade provides ±0.04% accuracy and 3 ppm/°C max drift. Consider the operating temperature range of −40°C to +125°C when designing for extreme environments.

Part Context

The ADR431AR belongs to the ADR43x series of ultralow noise XFET voltage references. This family shares common architectural features including low supply current and wide operating ranges, differentiated by their nominal output voltages. The ADR431 specifically targets applications requiring a stable 2.5 V reference with high precision and low noise characteristics.

Replacement Considerations

Direct substitutes include other parts within the ADR43x family such as the ADR431ARZ or ADR431ARMZ, which share identical electrical specifications but differ in packaging. Verify pin compatibility and thermal resistance values when transitioning between MSOP and SOIC packages.

FAQ

Does the ADR431AR require an external bypass capacitor?

No external capacitor is strictly required for stability, though a 0.1 µF capacitor at the output is recommended to improve noise suppression.

How can high-frequency noise be reduced if large capacitive loads are used?

An external RC network consisting of an 82 kΩ resistor and a 10 nF capacitor can be added between the COMP pin (Pin 7) and the output (Pin 6) to eliminate noise peaking caused by large capacitive loads.