AD9821KSTZRL7

Overview

The AD9821KSTZRL7 is a complete analog signal processor for imaging applications that do not require Correlated Double Sampling (CDS). It features a 40 MHz single-channel architecture designed to sample and condition the outputs of CMOS imagers and CCD arrays already containing on-chip CDS. The device operates from a single 3 V power supply, typically dissipating 150 mW, and is packaged in a 48-lead LQFP. Key specifications include a 12-bit ADC with a 2.0 V full-scale input range, a 0 dB to 36 dB variable gain amplifier (VGA) with 10-bit resolution, and a low noise optical black clamp circuit.

Feature Summary

• Integrates a differential input sample-and-hold amplifier, digitally controlled variable gain amplifier, black level clamp, and a 12-bit A/D converter into a single channel.
• Features a programmable 3-wire serial digital interface for internal register configuration, including gain adjustment, black level adjustment, and power-down modes.
• Includes an optical black clamp loop to remove residual offsets and track low-frequency variations in the black level during shielded pixel intervals.

Applications

• Digital still cameras using CMOS imagers
• Industrial and scientific imaging systems

Procurement Notes

Verify the specific ordering suffix KSTZRL7 against the manufacturer's current documentation to confirm package type, temperature range, and reel packaging details. Ensure compatibility with system voltage levels and timing requirements before integration.

Selection Notes

Select this component for imaging applications requiring a complete analog front end without on-chip CDS. Consider the 40 MHz maximum clock rate and 12-bit resolution when matching sensor output characteristics. Evaluate the 3 V single-supply operation and 150 mW power consumption against system thermal constraints.

Part Context

The AD9821 is part of Analog Devices' imaging signal processor family, designed specifically for conditioning signals from image sensors. It serves as an alternative to earlier models like the AD9801 and AD9803, offering a larger 2 V ADC full-scale range for improved noise performance.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Verify functional equivalence with other imaging signal processors if direct replacement is required.

FAQ

What is the maximum clock rate for the AD9821?

The maximum clock rate for the AD9821 is 40 MHz.

How is the VGA gain controlled?

The VGA gain is controlled via a 10-bit resolution setting through the 3-wire serial digital interface, providing a gain range of 0 dB to 36 dB.

What is the purpose of the Optical Black Clamp?

The Optical Black Clamp removes residual offsets in the signal chain and tracks low-frequency variations in the CCD's black level during shielded pixel intervals.