AD9945KCPRL

Overview

The AD9945KCPRL is a complete analog signal processor for CCD applications, featuring a 40 MHz single-channel architecture. It integrates a correlated double sampler (CDS), a digitally controlled variable gain amplifier (VGA) with 6 dB to 40 dB range, an optical black clamp circuit, and a 12-bit A/D converter. The device operates from a single 3 V supply, dissipating 160 mW in normal operation and 1.5 mW in power-down mode. Internal registers are programmed via a 3-wire serial interface supporting up to 10 MHz SCK frequency. It functions within a temperature range of -20°C to +85°C and utilizes a 32-lead LFCSP package.

Feature Summary

• Integrates a 40 MSPS correlated double sampler to reject low-frequency noise.
• Includes a 10-bit programmable variable gain amplifier for signal conditioning.
• Features a low-noise optical black clamp circuit for black level correction.
• Contains a 12-bit pipelined ADC with guaranteed no missing codes.

Applications

• Digital still cameras
• Digital video camcorders
• PC cameras
• Portable CCD imaging devices
• CCTV cameras

Procurement Notes

Verify the specific ordering suffix against the manufacturer's current documentation to confirm package type and RoHS compliance status. Confirm that the component meets the required operating temperature range and voltage specifications for the target application environment before finalizing procurement decisions.

Selection Notes

Select this component when a single-chip solution for CCD signal processing is required. Ensure the system timing generator can provide the necessary SHP, SHD, and DATACLK signals. Verify that the external coupling capacitor matches the DC restore requirements and that the digital interface logic levels are compatible with the host controller.

Part Context

The AD9945 serves as a dedicated analog front-end processor for area CCD arrays. It consolidates multiple signal conditioning stages into one package, reducing board space and design complexity. The device is designed to interface directly with CCD outputs, handling DC restoration, noise reduction, gain adjustment, and digitization in a unified workflow.

Replacement Considerations

The AD9945KCPZ is a verified equivalent part number offering identical functionality and pinout compatibility. Both variants share the same electrical characteristics and package dimensions, allowing for direct substitution in existing designs without hardware modifications.

FAQ

What is the required startup write sequence for the AD9945?

During power-up, the value 0x838 must be written into Register 0xD to ensure proper start-up operation of the internal circuits.

How is the VGA gain calculated?

The VGA gain in decibels is calculated using the formula: Gain (dB) = (VGA Code Value × 0.035 dB) + 5.3 dB.

What is the function of the CLPOB pulse?

The CLPOB pulse triggers the optical black clamp loop during the CCD's optical black pixel interval to remove residual offsets and track low-frequency black level variations.