ADR439AR

Overview

The ADR439AR is an ultralow noise XFET voltage reference with a fixed output of 4.5 V and ±0.12% initial accuracy (A Grade). It operates within a supply voltage range of 6.5 V to 18 V, requiring only 2 V of headroom. The device provides high output source current of +30 mA and sink current of −20 mA. Key electrical specifications include a maximum temperature coefficient of 10 ppm/°C, line regulation of 20 ppm/V, and load regulation of 15 ppm/mA. Quiescent current is typically 800 µA across the extended industrial temperature range of −40°C to +125°C.

Feature Summary

• Utilizes patented XFET technology for exceptionally low noise performance without requiring external capacitors.
• Features a dedicated trim terminal allowing output voltage adjustment over a 0.5% range.
• Capable of sourcing up to 30 mA and sinking up to 20 mA of output current.

Applications

• Precision data acquisition systems
• High resolution data converters
• Medical instruments

Procurement Notes

Verify the specific grade suffix (e.g., ARZ) against the required accuracy and temperature coefficient specifications. Confirm package type compatibility during procurement, as the component is available in both 8-lead MSOP and SOIC packages. Ensure the ordering part number matches the exact output voltage and tolerance requirements defined in the manufacturer's selection guide.

Selection Notes

Select this component when a stable 4.5 V reference is required with minimal low-frequency noise. The ADR439 is suitable for applications demanding high current drive capabilities, such as driving ADCs directly. Consider the B Grade variant if tighter accuracy and lower temperature drift are necessary for the specific design constraints.

Part Context

The ADR439AR belongs to the ADR43x series of XFET voltage references manufactured by Analog Devices. This family includes variants with different fixed output voltages ranging from 2.048 V to 5.0 V. All members share common architectural features, including low quiescent current operation and the ability to operate with reduced supply voltage headroom compared to traditional buried Zener references.

Replacement Considerations

Direct functional replacements within the same family include the ADR439B for improved accuracy or other ADR43x models for different voltage levels. Verify pinout compatibility between MSOP and SOIC packages if substituting based on footprint constraints.