AD7859ASZ-REEL

Overview

The AD7859ASZ-REEL is an 8-channel, 12-bit successive approximation register (SAR) analog-to-digital converter manufactured by Analog Devices. It operates from a single 3 V to 5.5 V supply and supports throughput rates up to 200 kSPS. The device features a flexible parallel interface with 16-bit or 8-bit data transfer options via DB0–DB15 pins. Key electrical specifications include a signal-to-noise ratio of 70 dB minimum, integral nonlinearity of ±1 LSB maximum, and differential nonlinearity of ±1 LSB maximum. Power consumption is typically 15 mW at 3 V in normal operation, with automatic power-down capabilities reducing dissipation significantly during idle periods.

Feature Summary

• Integrated self-calibration and system calibration functions ensure long-term accuracy across temperature variations.
• Flexible parallel I/O port supporting both 16-bit word and 8-bit byte data transfer modes.
• Multiple power management options including automatic power-down after conversion for low-power applications.
• Pseudo-differential input sampling scheme with track-and-hold amplifier for high-speed signal acquisition.

Applications

• Battery-powered systems such as personal digital assistants and mobile communications devices.
• Medical instruments requiring precise analog signal digitization.
• Instrumentation and control systems utilizing multi-channel data acquisition.
• High-speed modems and pen computers.

Procurement Notes

Verify the specific suffix REEL indicates tape-and-reel packaging when sourcing components. Confirm that the AD7859 variant matches the required 200 kSPS speed specification, distinct from the lower-speed AD7859L. Ensure compatibility with 3 V to 5.5 V supply rails and PQFP-44 package requirements for the target design.

Selection Notes

Select the AD7859 over the AD7859L if the application requires the higher 200 kSPS throughput rate. Consider the AD7859L only if the primary constraint is minimizing static power consumption at the expense of speed. Verify that the 12-bit resolution and pseudo-differential input architecture align with the sensor interface requirements.

Part Context

The AD7859 belongs to a family of high-speed, low-power sampling ADCs designed for battery-operated equipment. It shares architectural similarities with other SAR converters but distinguishes itself through integrated calibration memory and a versatile parallel interface. The component is part of Analog Devices' portfolio targeting portable electronics and industrial instrumentation markets.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should consult official Analog Devices resources for current cross-reference information regarding end-of-life status or alternative packages.