AD7722ASZ

Overview

The AD7722ASZ is a complete, low-power, 16-bit Sigma-Delta analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It operates from a single 5 V supply and features an on-chip 2.5 V voltage reference. The device accepts differential input voltages ranging from 0 V to +2.5 V or ±1.25 V centered around a common-mode bias. It provides 16-bit performance for input bandwidths up to 90.625 kHz with an output word rate of 195.3 kSPS when driven by a nominal 12.5 MHz clock. The part includes two cascaded finite impulse response (FIR) digital filters that reduce external antialiasing requirements. It supports both high-speed parallel and flexible serial interfaces for interfacing with digital signal processors.

Feature Summary

• Integrates a 16-bit Sigma-Delta modulator with dual FIR digital filters for inherent monotonicity and excellent linearity.
• Includes an accurate on-chip 2.5 V voltage reference with buffer capability for internal or external reference selection.
• Offers flexible data interface options via high-speed parallel port or 3-wire serial port compatible with DSPs.
• Features continuous analog sampling via the modulator, eliminating the need for external sample-and-hold circuitry.

Applications

• High-speed data acquisition systems requiring 16-bit resolution
• Industrial process control and monitoring
• Portable instrumentation with single-supply constraints
• Audio and vibration analysis applications

Procurement Notes

Verify the package type is the 44-lead MQFP (S-44-2) as specified in the datasheet. Confirm the temperature grade corresponds to the A version, which covers the industrial range of –40°C to +85°C. Ensure the ordering suffix matches the exact pinout and electrical specifications listed in the official Analog Devices documentation to avoid compatibility issues with existing designs.

Selection Notes

Select this component when a 16-bit resolution is required with output rates up to 220 kSPS. It is suitable for applications needing a single 5 V supply and integrated reference. Consider the parallel interface for maximum throughput or the serial interface for simplified PCB routing. Verify that the input bandwidth requirement does not exceed 90.625 kHz for optimal dynamic performance metrics.

Part Context

The AD7722 is part of Analog Devices' family of Sigma-Delta ADCs designed for precision measurement. It distinguishes itself by combining high speed with 16-bit resolution in a single-chip solution. The device is intended for systems where power consumption must be minimized while maintaining high accuracy and fast conversion rates without external analog front-end components.

Replacement Considerations

No public confirmed substitute part numbers are available in the provided documentation. Users should consult Analog Devices for current equivalent recommendations based on specific system requirements.

FAQ

What is the function of the UNI pin?

The UNI pin selects the analog input range. A logic low configures the device for unipolar operation (0 V to +2.5 V), while a logic high selects bipolar mode (±1.25 V).

How is the digital filter configured?

The AD7722 uses two cascaded finite impulse response (FIR) digital filters. The group delay is 215.5 µs, and the settling time for a step input is 431 µs when driven by a 12.5 MHz clock.

Can multiple AD7722 devices share a serial data line?

Yes, two AD7722s can be configured with their serial data outputs connected together. Each converter alternately transmits its conversion data on the shared serial data line using the TSI and DOE pins for control.