AD7821KRZ

Overview

The AD7821KRZ is an 8-bit analog-to-digital converter (ADC) utilizing a half-flash architecture and LC2MOS process. It features a built-in track-and-hold function with a maximum sampling rate of 1 MHz and a conversion time of 660 ns in WR-RD mode. The device supports unipolar input ranges from 0 V to +5 V or bipolar ranges of ±2.5 V, depending on the VSS pin configuration. It operates on a single +5 V supply for unipolar applications or dual ±5 V supplies for bipolar inputs. Key electrical parameters include a signal-to-noise ratio of 45 dB minimum, total unadjusted error of ±1 LSB, and power dissipation of 50 mW. The component is housed in a 20-lead SOIC package.

Feature Summary

• Half-flash conversion technique eliminates the need for external clock generation.
• Built-in track-and-hold function handles input signals up to 100 kHz without external components.
• Ratiometric reference inputs allow flexible unipolar and bipolar operation configurations.
• Standard microprocessor control signals enable direct interfacing with high-speed data buses.

Applications

• Digital signal processing systems requiring dynamic performance specifications.
• Voice recognition and echo cancellation circuits.
• Adaptive filtering applications.
• High-speed data acquisition systems.

Procurement Notes

Verify the specific suffix KRZ corresponds to the SOIC-20 package and commercial temperature range (-40°C to +85°C). Confirm that the ordering documentation matches the REV B datasheet specifications. Ensure compatibility with standard microprocessor interfaces before finalizing procurement orders.

Selection Notes

Select this model when an 8-bit resolution with 1 MHz sampling speed is required. Choose the AD7821KRZ over the AD7820 for improved conversion time and bandwidth. Consider the bipolar input capability if dual supplies are available. Verify that the 50 mW power dissipation fits within the thermal design constraints of the target application.

Part Context

The AD7821 series represents a high-speed improvement over the legacy AD7820. The KRZ variant specifically denotes the surface-mount SOIC package option. This component belongs to the Analog Devices LC2MOS family, combining precision bipolar circuits with low-power CMOS logic for mixed-signal applications.

Replacement Considerations

The MX7821KR+T is documented as a P-Compatible alternative offering similar 8-bit resolution and track-and-hold functionality. Verify pinout compatibility and electrical parameter alignment before substitution.