AD7824BQ

Overview

The AD7824BQ is a high-speed, multichannel analog-to-digital converter featuring four multiplexed analog input channels and an 8-bit resolution. It utilizes a half-flash conversion technique to achieve a fast conversion rate of 2.5 µs per channel, supporting a sampling frequency of up to 100 kHz. The device incorporates a built-in track-and-hold function capable of handling signals with frequencies up to 10 kHz and slew rates of 157 mV/µs without external conditioning. Operating from a single 5 V supply, it consumes typical power of 50 mW. The total unadjusted error is specified at ±1 LSB for this grade, and it interfaces via standard parallel logic using Chip Select and Read signals.

Feature Summary

• Half-flash architecture enables rapid conversion without requiring an external clock signal
• Integrated track-and-hold circuitry supports high-frequency signal acquisition on all channels
• Parallel digital interface allows direct connection to microprocessors using standard control signals
• Single 5 V supply operation simplifies system power requirements

Applications

• Multichannel data acquisition systems requiring cost-effective space-saving solutions
• Speech analysis applications utilizing real-time filtering techniques
• Fast infinite sample-and-hold circuits for multi-channel signal processing
• Microprocessor-based instrumentation interfacing via ROM-style memory mapping

Procurement Notes

Verify the specific ordering suffix BQ confirms the industrial temperature range of -40°C to +85°C and the ±1 LSB total unadjusted error specification. Confirm the package option Q-24 corresponds to the required 24-lead plastic quad flat pack or equivalent surface-mount configuration. Ensure compatibility with the intended voltage levels for the parallel data bus and control inputs before finalizing procurement.

Selection Notes

Select the AD7824BQ when four analog channels are sufficient for the application design. This model provides a tighter error specification compared to the K version but matches the L version's accuracy while offering the industrial temperature rating. Consider the AD7828 if eight channels are required, noting the reduced per-channel sampling rate. Verify that the source impedance driving the analog inputs remains low enough to meet the tracking time requirements.

Part Context

The AD7824 belongs to the LC2MOS family of high-speed ADCs manufactured by Analog Devices. This series combines CMOS process technology with linear circuit design to achieve low power consumption and high speed. The AD7824 specifically addresses the need for multichannel sampling in compact packages, serving as a bridge between slower successive approximation converters and more complex flash architectures.

Replacement Considerations

The AD7824LN offers the same package and functionality with a tighter error specification of ±1/2 LSB and commercial temperature range. The AD7824KN provides the same commercial range with ±1 LSB error. For eight-channel requirements, the AD7828 series serves as the expanded counterpart.