ADR445ARZ

Overview

The ADR445ARZ is a precision series 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 ±6 mV (A grade) or ±2 mV (B grade). The device features a temperature coefficient of 10 ppm/°C (A grade) or 3 ppm/°C (B grade) over the -40°C to +125°C range. It operates with a supply voltage headroom as low as 500 mV and supports sourcing up to 10 mA and sinking up to -5 mA.

Feature Summary

• XFET technology minimizes voltage change versus temperature nonlinearity for superior stability.
• Ultralow noise performance in the 0.1 Hz to 10 Hz frequency band.
• Low dropout operation requiring only 500 mV supply voltage headroom.
• Integrated TRIM pin allows output voltage adjustment without compromising performance.

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 (A or B) required for your application, as the datasheet distinguishes between them based on initial accuracy and temperature coefficient specifications. Confirm package availability, as the component is offered in both SOIC and MSOP formats. Ensure input capacitors are selected according to the stability requirements outlined in the basic connection diagrams.

Selection Notes

Select the ADR445ARZ when a stable 5.0 V reference is needed with minimal noise and drift. Consider the A grade for general precision needs or the B grade for tighter tolerance applications. Evaluate the quiescent current consumption against battery life requirements. Ensure the input voltage remains within the specified operating range to maintain regulation.

Part Context

The ADR445ARZ belongs to the ADR44x family of XFET voltage references, which includes models with various output voltages such as 2.048 V, 2.5 V, 3.0 V, and 4.096 V. This family shares common architectural features like low dropout capability and trim functionality. The 'ARZ' suffix indicates an 8-lead SOIC package that is RoHS compliant.

Replacement Considerations

Direct replacements within the same family include other ADR44x models if a different voltage level is acceptable. Cross-family alternatives may require verification of pin compatibility and thermal characteristics. Always confirm that substitute components meet the specific noise and drift requirements of the original design.

FAQ

How does the XFET technology improve performance compared to traditional references?

XFET technology uses junction field effect transistors with extra channel implants to generate a reference voltage. This results in lower noise and better temperature stability compared to buried Zener references, while maintaining low dropout operation.

What is the purpose of the TRIM pin on the ADR445ARZ?

The TRIM pin allows users to adjust the output voltage over a limited range (±0.5%) to compensate for system errors. It should be connected to a potentiometer between the output and ground, using low temperature coefficient resistors to maintain accuracy.