AD7822BRUZ

Overview

The AD7822BRUZ is an 8-bit, single-channel analog-to-digital converter (ADC) from Analog Devices Inc., featuring a maximum throughput of 2 MSPS. It utilizes a half-flash architecture with a conversion time of 420 ns and includes an on-chip track-and-hold amplifier. The device operates on a single supply voltage ranging from 3 V ± 10% to 5 V ± 10%, consuming up to 36 mW during normal operation. It provides a flexible parallel interface with an end-of-conversion pulse for standalone or microprocessor interfacing.

Feature Summary

• Integrates an on-chip 2.5 V reference and track-and-hold amplifier for simplified system design.
• Features a half-flash ADC structure enabling high-speed 420 ns conversion times.
• Includes an input offset adjust pin (VMID) to center the analog input span within the supply range.

Applications

• Data acquisition systems
• DSP front ends
• Disk drives
• Mobile communication systems

Procurement Notes

Verify the specific package variant, as the BRUZ suffix denotes a TSSOP-20 surface-mount package. Confirm that the ordering suffix matches the required reel or tube quantity if applicable. Ensure the component version aligns with the latest Rev. C datasheet specifications before finalizing procurement orders.

Selection Notes

Select this component when a single-channel, 8-bit resolution is required at speeds up to 2 MSPS. It is suitable for applications needing a wide operating supply range of 3 V or 5 V. Consider the AD7825 or AD7829 if multiple input channels are necessary instead of the single channel provided by the AD7822.

Part Context

The AD7822 is part of the AD7822/AD7825/AD7829 family of high-speed sampling ADCs. While sharing identical core performance characteristics such as resolution and speed, the family differentiates based on channel count: the AD7822 offers one channel, the AD7825 provides four, and the AD7829 supports eight channels.

Replacement Considerations

Direct functional equivalents within the same family include the AD7825BRUZ (4-channel) and AD7829BRUZ (8-channel). These share the same electrical specifications but differ in pin counts and channel configurations, requiring schematic adjustments for multiplexing.

FAQ

How does the VMID pin affect the analog input range?

The VMID pin allows the user to center the analog input span anywhere between AGND and VDD. Without an external connection, the default span is 0 V to 2.5 V for 5 V operation or 0 V to 2 V for 3 V operation.

What is the function of the CONVST pin regarding power consumption?

The CONVST pin initiates conversion and controls automatic power-down. If the logic level on CONVST is low at the end of a conversion, the device enters power-down mode to minimize current consumption.

Can the AD7822 operate without an external reference voltage?

Yes, the AD7822 contains an on-chip reference of 2.5 V with a 2% tolerance. An external reference can be used if higher precision is required, connected to the VREF IN/OUT pin.