AD7722AS-ES

Overview

The AD7722AS-ES is a 16-bit, low-power Sigma-Delta analog-to-digital converter (ADC) from 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 of 0 V to +2.5 V or ±1.25 V. It provides up to 220 kSPS output word rates with a 64x oversampling ratio. Key electrical parameters include a typical Signal-to-(Noise + Distortion) of 90 dB at 86 kHz bandwidth and Total Harmonic Distortion of -90 dB. The part is housed in a 44-lead MQFP package and is specified for the industrial temperature range of –40°C to +85°C.

Feature Summary

• 16-bit resolution with inherent monotonicity and on-chip calibration for zero-scale and full-scale error minimization.
• Integrated 2.5 V reference with buffer amplifier; supports external reference input via REF1/REF2 pins.
• Flexible interface supporting high-speed parallel data bus or 3-wire serial communication with DSPs.
• Dual-stage FIR digital filter providing linear phase response and reducing external antialiasing requirements.

Applications

• High-resolution data acquisition systems requiring precise DC and low-frequency AC measurements.
• Industrial process control instrumentation utilizing differential sensor inputs.
• Portable battery-powered instruments benefiting from low power consumption and single-supply operation.
• Medical equipment and ultrasound imaging channels requiring high linearity and dynamic range.

Procurement Notes

Verify the ES suffix against official Analog Devices documentation to confirm if it denotes a specific engineering sample, enhanced specification tier, or manufacturing lot code. Ensure the 44-lead MQFP package matches the target PCB footprint. Confirm that the industrial temperature grade (-40°C to +85°C) meets the operational environment requirements. Cross-reference the datasheet revision to ensure compatibility with existing design files.

Selection Notes

Select this component when 16-bit accuracy and low noise are critical for differential signal conditioning. The internal FIR filter simplifies anti-aliasing filter design compared to SAR ADCs. Consider the 5 V supply requirement and the need for a stable 12.5 MHz clock source. Evaluate the parallel vs. serial interface needs based on microcontroller or FPGA pin availability and data throughput requirements.

Part Context

The AD7722 is part of Analog Devices' portfolio of precision Sigma-Delta converters. It utilizes a continuous-time modulator architecture which eliminates the need for external sample-and-hold circuits. The device integrates the modulator, digital filters, and reference buffer into a single chip, reducing system complexity and board space compared to discrete solutions.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided source material. When evaluating alternatives, verify pin compatibility, resolution, sampling rate, and interface protocols. Ensure replacement devices support the required 5 V supply and differential input ranges.

FAQ

How does the AD7722 handle external antialiasing?

The integrated dual-stage FIR digital filter provides significant stop-band attenuation (90 dB), which reduces the requirements for external analog antialiasing filters, often allowing for first-order designs.

Can the AD7722 operate with an external reference?

Yes. While it includes an accurate on-chip 2.5 V reference, the REF1 pin can be driven by an external reference voltage (2.32 V to 2.62 V) if higher precision or different scaling is required.

What is the maximum clock frequency for the AD7722?

The device is specified for a nominal clock input frequency of 12.5 MHz, but the absolute maximum rating allows for frequencies up to 15 MHz.