AD7821KNZ

Overview

The AD7821KNZ is an 8-bit analog-to-digital converter utilizing a half-flash conversion technique. It features a maximum conversion time of 660 ns and supports a sampling rate up to 1 MHz. The device includes a built-in track-and-hold function with a bandwidth of 100 kHz, eliminating the need for external clock generation. It operates from a single +5 V supply for unipolar inputs or dual ±5 V supplies for bipolar ranges. 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 Plastic DIP package.

Feature Summary

• Half-flash architecture enables high-speed conversion without external clocks
• Integrated track-and-hold handles input signals up to 100 kHz
• Flexible reference inputs support both unipolar and bipolar operation modes
• Standard microprocessor interface with latched three-state data outputs

Applications

• Digital signal processing systems requiring precise sampling intervals
• Voice recognition and echo cancellation circuits
• Adaptive filtering applications

Procurement Notes

Verify the specific suffix KNZ corresponds to the 20-lead Plastic DIP package and the –40 °C to +85°C operating temperature range. Confirm that the ordering documentation explicitly lists this part number variant before finalizing procurement decisions.

Selection Notes

Select this component when an 8-bit resolution with a 660 ns conversion speed is required. Ensure the application can accommodate the 100 kHz input bandwidth limitation of the internal track-and-hold. Verify compatibility with standard microprocessor control signals such as CS, RD, and WR.

Part Context

This model belongs to the AD7821 series of high-speed ADCs. It serves as an improved version over the AD7820, offering faster conversion times and higher signal bandwidth. The series utilizes Linear Compatible CMOS (LC2MOS) technology to combine precision bipolar circuits with low power CMOS logic.

Replacement Considerations

The AD7820 is a related model within the same family but offers slower performance characteristics. Direct substitution requires verifying that the system timing constraints can tolerate the AD7820's longer conversion time.