AD9843AJSTZ

Overview

The AD9843AJSTZ is a complete analog signal processor for CCD applications, featuring a 20 MHz single-channel architecture. It samples and conditions outputs of interlaced and progressive scan area CCD arrays. The signal chain includes an input clamp, correlated double sampler (CDS), digitally controlled variable gain amplifier (VGA), black level clamp, and a 10-bit A/D converter. Operating from a single 3 V supply, it dissipates 78 mW in normal mode. Key parameters include a 20 MSPS maximum clock rate, 10-bit ADC resolution with no missing codes, and a full-scale input voltage of 2.0 V. Power consumption varies by mode: 45 mW in fast recovery, 5 mW in standby, and 1 mW in total power-down.

Feature Summary

• Integrates a 20 MSPS Correlated Double Sampler (CDS) with programmable gain ranging from -2 dB to +10 dB.
• Includes a Variable Gain Amplifier (VGA) offering a gain range of 2 dB to 36 dB with 10-bit resolution control.
• Features low noise clamp circuits and an analog preblanking function for accurate signal conditioning.
• Utilizes a 3-wire serial digital interface for programming internal registers such as gain, black level, and power modes.

Applications

• Digital Still Cameras
• Digital Video Camcorders
• PC Cameras

Procurement Notes

Verify the part number suffix Z indicates RoHS compliance when sourcing. Confirm the operating temperature range matches the application requirements, specifically the -20°C to +85°C specification for the AJ variant. Ensure the 48-lead LQFP package footprint aligns with the PCB design. Check that the 3 V single supply voltage is compatible with the system power rails.

Selection Notes

Select this component for CCD signal processing requiring integrated CDS and VGA functions. Consider the 2 V full-scale ADC input range compared to older 1 V designs for improved noise performance. Evaluate the power consumption specifications against thermal constraints, noting the 78 mW typical dissipation. Verify compatibility with the target image processing ASIC via the 3-wire serial interface timing requirements.

Part Context

The AD9843A belongs to Analog Devices' family of complete CCD signal processors. It succeeds earlier models like the AD9801 and AD9803 by providing a larger 2 V ADC full-scale range. This architecture improves overall signal-to-noise ratio. The device integrates multiple analog front-end stages into a single chip, reducing external component count for digital imaging systems.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Designers should verify pinout and register compatibility if considering alternative CCD signal processors from other manufacturers or different Analog Devices families.