AD7921AUJ-REEL7

Overview

The AD7921AUJ-REEL7 is a dual-channel, 12-bit successive approximation analog-to-digital converter manufactured by Analog Devices Inc. It operates from a single supply voltage ranging from 2.35 V to 5.25 V and supports throughput rates up to 250 kSPS. The device features an on-chip track-and-hold amplifier with a wide input bandwidth capable of handling frequencies exceeding 6 MHz. It utilizes an external reference derived from the power supply, eliminating the need for an internal reference. The component is housed in an 8-lead TSOT package and includes a flexible serial interface compatible with standard microprocessor protocols.

Feature Summary

• Dual-channel architecture with integrated track-and-hold amplifier
• Low power consumption with configurable power-down modes
• Flexible serial interface supporting multiple communication protocols
• Reference voltage derived directly from the power supply

Applications

• Battery-powered systems such as personal digital assistants
• Medical instruments requiring low power operation
• Mobile communications equipment
• Instrumentation and control systems
• Data acquisition systems

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm package type and reel specifications. Ensure compatibility with system voltage requirements and interface timing constraints before integration. Cross-reference manufacturer part numbers with distributor listings to confirm authenticity and revision status.

Selection Notes

Select this component when a dual-channel solution with 12-bit resolution and high throughput is required. Consider the TSOT package for space-constrained designs. Evaluate power consumption profiles against system battery life requirements, noting the significant reduction in current draw during power-down states.

Part Context

This component belongs to the AD7911/AD7921 family of high-speed, low-power ADCs. The AD7921 variant specifically provides 12-bit resolution compared to the 10-bit AD7911. Both share identical pinouts, interfaces, and power characteristics, differing primarily in conversion accuracy and data output length.

Replacement Considerations

The AD7911AUJ-REEL7 serves as a functional substitute within the same family, offering 10-bit resolution instead of 12-bit. Verify that the reduced resolution meets application accuracy requirements before substitution.

FAQ

How is the channel selection determined during conversion?

Channel selection is controlled via the DIN pin. The channel to be converted is selected by writing to the third most significant bit on the DIN input, which is clocked into an internal register on the falling edge of the serial clock.

What is the maximum operating temperature range for the A Grade version?

The A Grade version of the AD7921 is specified for an operating temperature range from -40°C to +85°C.

Does the device require an external voltage reference?

No external reference is required. The reference for the ADC is taken internally from the VDD power supply, allowing for the widest dynamic input range.