AD7829BRUZ-REEL

Overview

The AD7829BRUZ-REEL is an 8-channel, 8-bit analog-to-digital converter (ADC) from Analog Devices Inc., operating at a maximum throughput of 2 MSPS. It utilizes a half-flash architecture with a conversion time of 420 ns and features an on-chip track-and-hold amplifier. The device supports single-ended inputs with a flexible parallel interface and includes an internal 2.5 V reference. It operates on a wide supply range of 3 V ± 10% or 5 V ± 10%, consuming 24 mW typically in normal operation. Packaged in a 28-lead TSSOP, it is designed for high-speed data acquisition and DSP front-end applications.

Feature Summary

• Integrates an 8-bit half-flash ADC with a 420 ns conversion time and an on-chip track-and-hold amplifier capable of handling input frequencies up to 10 MHz.
• Features eight single-ended analog input channels selectable via address pins without requiring software writes, alongside an automatic power-down mode triggered by the CONVST pin state.
• Includes an on-chip 2.5 V reference and a VMID pin that allows adjustment of the analog input span center point within the supply voltage range.

Applications

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

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm packaging details, as reel specifications may vary. Ensure compatibility with the required supply voltage range and logic levels before integration. Cross-reference the datasheet revision to confirm performance parameters match the intended application requirements.

Selection Notes

Select this component when eight single-ended channels are required at speeds up to 2 MSPS. The half-flash architecture offers faster conversion times compared to SAR types but consumes more power. Consider the VMID pin utility for offset adjustments if system offsets exist. Verify that the parallel interface timing meets the microprocessor or DSP bus requirements.

Part Context

The AD7829 is part of the AD7822/AD7825/AD7829 family, which provides 1-, 4-, and 8-channel variants respectively. All members share the same core architecture, including the 8-bit half-flash ADC, on-chip reference, and track-and-hold amplifier. The primary distinction lies in the number of analog input channels available, allowing designers to scale channel count without changing the fundamental interface or control logic.

Replacement Considerations

The AD7829BRUZ-1 is listed as a parameter-equivalent alternative within the same product family. Both devices share identical electrical characteristics and functionality, differing primarily in packaging or minor manufacturing revisions. Verify pinout compatibility and ensure the replacement variant meets the specific thermal and mechanical constraints of the existing design.

FAQ

How is the analog input span centered?

The input span is centered using the VMID pin. If left unconnected, the default span is AGND to 2.0 V for 3 V supplies or AGND to 2.5 V for 5 V supplies. An external voltage can be applied to shift this range.

What triggers the automatic power-down mode?

Automatic power-down occurs at the end of a conversion if the CONVST pin is logic low when the End of Conversion (EOC) signal goes high. This feature helps reduce power consumption during idle periods.

Can the device operate with an external reference?

Yes, an external reference can be connected to the VREF IN/OUT pin. When using an external reference, the on-chip reference is bypassed, and the power-up time is reduced to 1 μs max compared to 25 μs typ with the internal reference.