AD7821BQ

Overview

The AD7821BQ is an 8-bit analog-to-digital converter featuring a built-in track-and-hold function and half-flash conversion architecture. It operates on a single +5 V supply for unipolar inputs (0 to +5 V) or dual ±5 V supplies for bipolar inputs (±2.5 V). The device achieves a maximum sampling rate of 1 MHz with a conversion time of 660 ns in WR-RD mode. Key electrical parameters include a signal-to-noise ratio of 45 dB minimum, total unadjusted error of ±1 LSB max, and power dissipation of 50 mW typ. It utilizes standard microprocessor control signals and provides latched three-state data outputs.

Feature Summary

• Built-in track-and-hold capability allows digitization of full-scale signals up to 100 kHz without external components.
• Half-flash conversion technique eliminates the need for an external clock signal.
• Supports both unipolar and bipolar input ranges through flexible reference and supply configurations.
• Designed for direct interfacing with standard microprocessors using common control signals.

Applications

• Digital signal processing systems requiring dynamic performance specifications
• Voice recognition and echo cancellation applications
• Adaptive filtering circuits

Procurement Notes

Verify the specific suffix B indicates the industrial temperature range (-40°C to +85°C) and Q denotes the Cerdip package option as defined in the ordering guide. Confirm that the component matches the REV. B datasheet specifications before integration. Ensure supply voltage and reference connections align with the selected unipolar or bipolar operating mode.

Selection Notes

Select this model when an 8-bit resolution with high-speed conversion is required alongside low power consumption. The AD7821BQ is suitable for designs needing a 1 MHz sample rate without external clocking circuitry. Consider the Cerdip package for specific thermal or mechanical constraints. Verify that the system can accommodate the required ±5 V supply if bipolar operation is necessary.

Part Context

The AD7821 series represents a high-speed 8-bit ADC family fabricated in LC2MOS technology. The AD7821BQ specifically belongs to the industrial temperature grade within this lineup. It serves as an improved version over the AD7820, offering faster conversion times and higher signal bandwidth. The part is designed for applications demanding precise timing and low jitter characteristics.

Replacement Considerations

The AD7821KN, AD7821KP, and AD7821KR are compatible alternatives within the same series offering identical electrical performance but different package options. For extended temperature requirements, the AD7821TQ or AD7821TE models provide operation down to -55°C. Ensure pin compatibility and package dimensions match the existing design layout.