ADR445ARMZ

Overview

The ADR445ARMZ is a precision voltage reference from Analog Devices, utilizing XFET technology to deliver ultralow noise and high accuracy. It provides a fixed output of 5.0 V with an initial accuracy of ±2 mV (±0.04%) for the B grade. The device features a temperature coefficient of 3 ppm/°C over the extended industrial range of −40°C to +125°C. It operates with a low dropout headroom of 500 mV, supporting input voltages from 5.5 V to 18 V. Quiescent current is typically 3.75 mA, while it can source up to 10 mA and sink up to 5 mA. Noise performance is specified at 2.25 µV p-p in the 0.1 Hz to 10 Hz band.

Feature Summary

• XFET technology minimizes voltage change versus temperature nonlinearity for superior stability.
• Capable of sourcing 10 mA and sinking 5 mA output current for flexible load driving.
• Includes a dedicated TRIM pin allowing output voltage adjustment within a 0.5% range.
• Operates effectively with minimal supply voltage headroom of 500 mV.

Applications

• Precision data acquisition systems
• High resolution data converters
• Battery-powered instrumentation
• Portable medical instruments
• Industrial process control systems

Procurement Notes

Verify the specific electrical grade required for your application, as the ADR445 series includes both A grade (10 ppm/°C) and B grade (3 ppm/°C) options. Confirm that the SOIC-8 package matches your PCB footprint requirements. Ensure input voltage constraints are met, as the minimum operating voltage is 5.5 V. Check for any specific long-term stability requirements, as drift characteristics vary by production batch.

Selection Notes

Select the ADR445ARMZ when system design demands low noise combined with high DC accuracy. The B grade variant is suitable for applications requiring tight temperature coefficients. Consider the available trim functionality if precise calibration against system errors is necessary. Evaluate thermal resistance specifications if operating near maximum power dissipation limits in enclosed environments.

Part Context

This component belongs to the ADR440/ADR441/ADR443/ADR444/ADR445 family of XFET voltage references. These devices share common architectural features, including low dropout operation and similar pin configurations across MSOP and SOIC packages. The family is designed to replace traditional buried Zener references in high-end signal conversion applications where noise and drift are critical parameters.

Replacement Considerations

Direct functional replacements within the same family include other ADR44x models with different nominal voltages but identical package and performance characteristics. Verify compatibility regarding input voltage ranges and output current capabilities before substitution.

FAQ

What is the purpose of the TRIM pin on the ADR445?

The TRIM pin allows users to adjust the output voltage over a 0.5% range to compensate for system errors or reference inaccuracies without compromising overall performance.

How does the ADR445 handle capacitive loads?

The datasheet specifies a 0.1 µF capacitor on the output for stability. Larger capacitors may require evaluation of stability, particularly under varying load conditions.