ADR421BR

Overview

The ADR421BR is a second-generation XFET voltage reference providing a fixed 2.500 V output with B Grade accuracy of ±0.04% and a temperature coefficient of 3 ppm/°C. It operates within an input voltage range of 4.5 V to 18 V, drawing a maximum quiescent current of 500 µA while delivering up to 10 mA of load current. The device features low noise (1.75 µV p-p from 0.1 Hz to 10 Hz) and long-term stability of 50 ppm per 1000 hours. It is housed in an 8-lead SOIC package and functions reliably across an extended industrial temperature range of −40°C to +125°C.

Feature Summary

• Utilizes patented XFET technology for superior thermal hysteresis and low noise compared to band gap references.
• Includes a dedicated trim terminal allowing output voltage adjustment over a ±0.5% range without compromising temperature coefficients.
• Offers high output drive capability of 10 mA with minimal supply headroom requirements.

Applications

• Precision data acquisition systems
• High resolution converters
• Portable medical instruments
• Optical network control circuits

Procurement Notes

Verify the specific suffix 'BR' corresponds to the B Grade electrical specifications, including the ±0.04% initial accuracy and 3 ppm/°C temperature coefficient. Confirm the package type matches the required 8-lead SOIC footprint. Ensure the operating environment falls within the specified -40°C to +125°C range to maintain guaranteed performance levels.

Selection Notes

Select this component when ultra-low noise and high precision are critical for signal integrity. The B Grade variant is suitable for applications requiring tighter initial accuracy than the standard A Grade. Consider the trim pin utility if system-level calibration is necessary to compensate for external circuit errors.

Part Context

Part of the ADR42x series of ultraprecision voltage references, which includes variants with different nominal outputs such as 2.048 V, 3.00 V, and 5.00 V. All members share the same XFET architecture and package options, ensuring consistent performance characteristics across the family for scalable design implementations.

Replacement Considerations

ADR421ARZ

FAQ

How does the trim terminal affect the temperature coefficient?

Adjusting the output voltage via the trim terminal has a negligible effect on the temperature coefficient, provided that low temperature coefficient components are used in the trimming circuit.

Is an output capacitor required for stability?

No, the ADR421 does not require an output capacitor for stability under any load condition, though one may be added to filter noise or improve transient response.