ADR421ARZ-REEL7

Overview

The ADR421ARZ-REEL7 is a second-generation XFET voltage reference with a fixed 2.500 V output in an 8-lead SOIC package. It provides an initial accuracy of ±0.12% and a temperature coefficient of 10 ppm/°C. The device operates within a supply range of 4.5 V to 18 V, drawing a maximum quiescent current of 500 µA. It delivers up to 10 mA of output current while maintaining low noise of 1.75 µV p-p from 0.1 Hz to 10 Hz. Long-term stability is rated at 50 ppm per 1000 hours.

Feature Summary

• Utilizes patented eXtra implanted junction FET (XFET) technology for superior accuracy and thermal hysteresis compared to standard band gap references.
• Features a dedicated trim terminal allowing output voltage adjustment over a ±0.5% range without compromising temperature coefficient performance.
• Incorporates curvature correction techniques to minimize nonlinearity of the voltage change across the operating temperature range.

Applications

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

Procurement Notes

Verify the specific electrical grade required, as the datasheet defines distinct A Grade and B Grade specifications for accuracy and temperature coefficient. Confirm that the SOIC-8 package footprint matches the design constraints. Ensure input voltage headroom requirements are met, as the device requires a minimum differential between VIN and VOUT for proper regulation.

Selection Notes

Select this component when low noise and high precision are critical for signal integrity in analog front ends. Consider the A Grade variant if tighter initial accuracy or lower temperature coefficients are necessary for the application. Evaluate the thermal resistance characteristics if the device will operate under high load currents or elevated ambient temperatures.

Part Context

This part belongs to the ADR42x series of ultraprecision voltage references manufactured by Analog Devices. The series includes variants with different nominal output voltages, such as the ADR420 (2.048 V), ADR423 (3.00 V), and ADR425 (5.00 V). All members share the same XFET architecture and package options.

Replacement Considerations

Direct functional substitutes within the same family include the ADR420ARZ, ADR423ARZ, and ADR425ARZ, provided the output voltage difference is acceptable for the circuit design. Other packages like the MSOP-8 (ADR421ARMZ) offer pin-compatible alternatives for space-constrained designs.

FAQ

Can the output voltage be adjusted?

Yes, the TRIM pin allows the output voltage to be adjusted over a ±0.5% range without affecting the temperature coefficient.

Is an output capacitor required for stability?

No, the ADR42x does not require an output capacitor for stability under any load condition, though one can be added to filter noise.