CCDs and CMOS imagers get better front ends

Analog Devices has announced two analog front-end converters that it is targeting at both CMOS and CCD digital imaging applications.

Analog Devices has announced two analog front-end (AFE) converters that it is targeting at both CMOS and CCD digital imaging applications.

The AD9821 features a 12-bit, 40-MSPS ADC that interfaces with high-speed CMOS sensors via a differential sensor input. It is designed to interface with CMOS imagers used in applications for which image quality is essential, such as medical imaging, microscopy, and industrial/machine vision.

The chip also includes a low-noise optical black clamp and a 0-to-36 dB, 10-bit programmable gain amplifier. It dissipates just 150 mW, enabling longer battery life in portable applications.

The AD9845B, on the other hand, is a 12-bit, 30-MSPS AFE designed for high-speed, high-resolution CCD (charge-coupled devices) imaging applications, such as scientific and industrial imaging devices, as well as digital still cameras and camcorders.

The device improves upon the standard AFE resolution of 10 bits, delivering image quality 4 times higher and 1.5 times faster than any standard AFE on the market, according to Analog Devices. In addition, the AD9845B features an integrated 6-bit resolution PxGA (pixel gain amplifier) that enables better image quality, by allowing gain to be finely tuned to fit the image.

The AD9845B also includes a 30-MSPS CDS (correlated double sampler) and a 2 dB to 36 dB 10-bit VGA (variable gain amplifier). It also provides an input clamp, black level clamp, and input modes for processing analog video signals. Its internal registers are programmed through a 3-wire serial digital interface. Programmable features include gain adjustment, black level adjustment, input confirmation and power-down modes. The device operates from a single 3 V power supply and typically dissipates 153 mW.

The AD9821 comes in a 48-LQFP package and is priced at $13.02 per unit in 100-piece quantities. The AD9845B is available in a 48-pin LQFP package and is fully pin-compatible with all products in ADI’s AD984x family of AFE products for the CCD imaging market. It is priced at $11.71 per unit in 100-piece quantities. Samples of both parts are available now.

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