AD7872JRZ-REEL

Overview

The AD7872JRZ-REEL is a complete monolithic 14-bit analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It utilizes a successive approximation register (SAR) architecture and operates from ±5 V power supplies, accepting bipolar input signals within a ±3 V range. The device features an internal laser-trimmed clock oscillator, eliminating the need for external timing components. It provides a throughput rate of 83 kSPS with a typical power dissipation of 50 mW. The component is housed in a 16-pin SOIC package and supports serial data output formats compatible with modern microprocessors.

Feature Summary

• Integrated track-and-hold amplifier enables accurate conversion of full-power signals up to 41.5 kHz.
• On-chip buried Zener reference provides a stable 3 V source without requiring external components.
• Versatile interface logic allows synchronization with digital systems via internal or external clock sources.

Applications

• Digital signal processing
• High speed modems
• Speech recognition and synthesis
• Spectrum analysis
• DSP servo control

Procurement Notes

Verify that the ordering suffix REEL indicates reel packaging rather than tube packaging when sourcing this specific part number. Confirm the J temperature grade corresponds to the required commercial operating range of 0°C to +70°C. Ensure the serial-only interface matches the system design requirements, as parallel variants exist within the same family.

Selection Notes

Select the AD7872 variant specifically when a serial data interface is required, distinguishing it from the AD7871 which offers parallel and byte options. Consider the 14-bit resolution and 83 kSPS throughput against system bandwidth needs. Verify compatibility with ±5 V supply rails and ensure the single-ended input configuration meets the application's signal conditioning requirements.

Part Context

This component belongs to the AD7871/AD7872 family of fast, complete 14-bit sampling ADCs. Fabricated using Analog Devices' LC2MOS mixed technology process, these devices integrate a SAR ADC, DAC, and control logic on a single chip. The AD7872 serves as the serial-output counterpart to the multi-interface AD7871, maintaining identical dynamic performance and power characteristics.

Replacement Considerations

Public confirmed substitute part numbers include AD7872KRZ.

FAQ

How is the internal clock enabled on the AD7872?

The internal laser-trimmed oscillator is enabled by tying the CLK pin (Pin 3) to VSS. Alternatively, an external TTL-compatible clock may be applied to this pin.

What is the function of the CREF pin?

The CREF pin serves as the decoupling point for the on-chip reference. A 10 nF capacitor should be connected between this pin and AGND to minimize reference noise.

Can the AD7872 operate with unipolar inputs?

Yes, unipolar operation is supported by using the REF OUT pin to offset the analog input by 3 V. The resistor network determines the specific unipolar range, such as 0 V to 5 V or 0 V to 10 V.