Analog Devices' 256-ch 16-bit digital X-ray AFE combines low noise and power with high image quality

Analog Devices has introduced a highly integrated digital X-ray AFE (analog front end) that combines low-noise performance in multiple power-mode options with high image quality. The 256-channel ADAS1256 digital X-ray AFE integrates the complete charge-to-digital conversion signal chain by incorporating low-noise programmable charge amplifiers, correlated double-sampling circuitry, and 16-bit ADCs. With a noise figure equivalent to the charge of 560 electrons at a 2-picocoulomb full-scale range, the ADAS1256 enables high-resolution digital X-ray images while reducing patient X-ray dose exposure. The ADAS1256 has multiple functional power modes ranging from 1- to 3-mW/ch, allowing manufacturers to address a wide range of digital X-ray modalities including portable radiology and mammography as well as high speed fluoroscopy and cardiac imaging. "Thanks to the ultra-low-noise profile and dynamic range of the ADAS1256, digital X-ray technology will continue to deliver better diagnostic image quality and reduce radiation dosage applied to patients compared to existing digital X-ray systems," said Pat O'Doherty, vice president, healthcare group, Analog Devices. "By achieving this level of performance while adhering to a strict power budget, the ADAS1256 digital X-ray AFE provides medical equipment designers with a single device that serves the growing high-performance requirements of the portable digital X-ray market." The ADAS1256 is a 256-channel, simultaneous-sampling, high-dynamic-range, low-power AFE that is a complete charge-to-digital conversion signal chain. It incorporates 256 low-noise integrators, low-pass filters, and correlated double samplers that are multiplexed into a high-speed, 16-bit, ADC. All converted channel results are output on a single LVDS self-clocked serial interface. The ADAS1256 is programmable using an SPI-compatible daisy-chain serial interface. ADI delivers the AFE in a high-density system-on-flex (SOF) package that can mount directly on a digital X-ray panel. ADAS1256 Digital X-Ray AFE Key Features

• Single-chip, 256-channel, charge-to-digital conversion
• 16-bit resolution with no missing codes
• Simultaneous sampling
• User adjustable full-scale range up to 32 pC
• Ultralow noise: 560 e? at 2 pC range
• Multiple functional power modes: from 1- to 3-mW/ch
• Power-down and sleep modes down to 5 ?W/ch