Analogue front ends improve their images

New from Analog Devices are a pair of state-of-the-art analogue front-end convertors for digital imaging using CMOS image sensors and CCDs.

New from Analog Devices are a pair of state-of-the-art analogue front-end (AFE) convertors for digital imaging using CMOS image sensors and CCDs.

The AD9821 is the industry's first 12bit, 40Msample/s AFE for interfacing with CMOS image sensors used in applications for which image quality is essential, such as medical imaging, microscopy, industrial/machine vision, digital photography, biometrics and automatic inspection equipment.

An alternative to component-based solutions using several ICs performing discrete functions, the AD9821 provides all the functionality needed to digitise an image from a CMOS image sensor on a single, integrated chip.

The AD9821 features a 12bit, 40Msample/s ADC that interfaces with high-speed CMOS sensors via a differential sensor input.

It includes a low-noise optical black clamp and a 0-36dB, 10bit programmable gain amplifier.

The AD9821 dissipates only 150mW, enabling longer battery life in portable applications.

The AD9845B is the industry's highest performance 12bit, 30Msample/s AFE and is designed for high-speed, high-resolution CCD imaging applications, such as scientific and industrial imaging devices, as well as digital still cameras and camcorders.

Addressing designer demand for higher resolution images produced at faster bit rates, the AD9845B improves upon the standard AFE resolution of 10bit, delivering image quality four times higher and 150% faster than any standard AFE on the market.

In addition, the AD9845B features an integrated 6bit resolution PxGA (pixel gain amplifier) that enables better image quality, by allowing gain to be finely tuned to fit the image.

The AD9845B includes a 12bit 30Msample/s ADC, a 30Msample/s correlated double sampler, a 4 +/-6dB 6bit PxGA and a 2-36dB 10bit variable gain amplifier.

It also provides an input clamp, black level clamp, and input modes for processing analogue video signals.

Its internal registers are programmed through a three-wire serial digital interface.

Programmable features include gain adjustment, black level adjustment, input confirmation and power-down modes.

The AD9845B operates from a single 3V power supply and typically dissipates 153mW.

The AD9821 comes in a tiny (7 x 7mm) 48-LQFP package and is priced at $13.02 per unit in 100-piece quantities.

The AD9845B is available in a compact, 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 devices are available now.

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