AD8643ARZ

Overview

The AD8643ARZ is a quad precision JFET input amplifier featuring rail-to-rail output and low power consumption. It operates on single supplies from 5 V to 26 V or dual supplies of ±2.5 V to ±13 V. Key electrical parameters include a maximum supply current of 250 μA, an input bias current of 1 pA, and an offset voltage of 750 μV. The device offers a gain bandwidth product of 3 MHz and a slew rate of 2 V/μs at 5 V. It is housed in a 14-lead SOIC package and functions reliably within the extended industrial temperature range of −40°C to +125°C.

Feature Summary

• JFET input stage providing extremely low input bias current for high impedance signal sources.
• Rail-to-rail output capability enabling full dynamic range utilization in single-supply systems.
• Unity-gain stability with no phase reversal when driven beyond the common-mode range.
• Low quiescent current design suitable for battery-powered and heat-sensitive applications.

Applications

• Photodiode amplifiers
• Precision current sensing
• Line- or battery-powered instruments
• Medical instrumentation

Procurement Notes

Verify the specific ordering suffix to confirm the package type, as the AD8643 series includes both SOIC and LFCSP options. Ensure the RoHS compliant designation (Z) matches environmental requirements. Confirm that the 14-lead SOIC package aligns with the PCB footprint and thermal management strategy for the target application environment.

Selection Notes

Select this component for designs requiring multiple channels with minimal power dissipation and high input impedance. The quad configuration reduces board space compared to individual amplifiers. Consider the 3 MHz bandwidth and 2 V/μs slew rate for moderate-speed signal processing tasks where DC accuracy and low noise are prioritized over high-frequency performance.

Part Context

The AD8643ARZ belongs to the AD8641/AD8642/AD8643 family of low power, precision JFET amplifiers manufactured by Analog Devices. This series is designed to provide high DC accuracy and AC performance while maintaining low power consumption. The ARZ variant specifically denotes the 14-lead standard small outline package version of the quad amplifier.

Replacement Considerations

The AD8643ACPZ serves as a package alternative offering the same electrical characteristics in a 16-lead LFCSP format. Verify pinout compatibility and thermal pad connections when substituting between the SOIC and LFCSP packages.