AD7921ARMZ

Overview

The AD7921ARMZ is a dual-channel, 12-bit successive approximation analog-to-digital converter (ADC) manufactured by Analog Devices Inc. It operates from a single power supply ranging from 2.35 V to 5.25 V and supports throughput rates up to 250 kSPS. The device features an internal track-and-hold amplifier capable of handling input frequencies exceeding 6 MHz. Power dissipation is typically 4 mW at 250 kSPS with 3 V supplies and 13.5 mW with 5 V supplies. The part utilizes a flexible serial interface compatible with SPI, QSPI, MICROWIRE, and DSP standards. It includes a standby mode with maximum current consumption of 1 μA.

Feature Summary

• Dual-channel architecture with on-chip multiplexing for efficient signal acquisition
• Internal reference derived from the power supply to maximize dynamic input range
• Flexible power management with low-power standby mode for extended battery life
• Standard serial interface supporting multiple communication protocols without pipeline delays

Applications

• Battery-powered personal digital assistants and mobile communications devices
• Medical instruments requiring precise analog signal digitization
• Data acquisition systems in instrumentation and control environments
• High-speed modems and optical sensor interfaces

Procurement Notes

Verify the specific ordering suffix against official Analog Devices documentation to confirm package type and reel specifications. Ensure compatibility with system voltage requirements between 2.35 V and 5.25 V. Confirm that the MSOP-8 package dimensions meet PCB layout constraints. Validate that the serial clock frequency does not exceed 5 MHz for guaranteed performance specifications.

Selection Notes

Select the AD7921ARMZ when 12-bit resolution is required for dual-channel applications. Compare against the AD7911 if 10-bit resolution suffices for lower cost or power constraints. Consider the operating temperature range of -40°C to +85°C for industrial environments. Evaluate power consumption profiles based on the specific throughput rate and supply voltage used in the design.

Part Context

The AD7921 is part of the AD7911/AD7921 family of high-speed, low-power ADCs. It shares the same pinout and interface characteristics as the 10-bit AD7911 but offers higher resolution. Both devices utilize the same MSOP-8 and TSOT-8 packages. The family is designed for applications requiring moderate speed and precision in compact form factors.

Replacement Considerations

The AD7911ARMZ is a functional substitute within the same family, offering identical pinouts and interfaces but with 10-bit resolution instead of 12-bit. Verify that the reduced resolution meets application accuracy requirements before substitution.