Ams introduces a new 256-channel ADC

     Ams has announced the introduction of a 256-channel analog digital converter, the AS5911, for the digitization of photodiode array signals in high-performance computed tomography (CT) devices. The converter is a system-level packaging solution that enables simultaneous digital current conversion of 256 photodiode outputs in a CT detector in a 14mm x 14mm FBGA package.

     The AS5911 has on-chip calibration for bias voltage, linearity, bias charge, and leakage current. This automatically sets the photodiode and the front end at the ideal operating point, compensating the signal chain for bias and nonlinearity. The embedded automatic calibration capability reduces the development effort in the data acquisition system and enables the use of low-cost FPGas that require less computing power.

     Ams's proprietary ADC architecture has zero stagnation time and provides a good balance between power and noise performance. In low noise mode, when the input current range is 0.5µA, the input reference noise is lower than 0.29fC. Low noise is the hallmark of high performance CT detectors and is essential for imaging quality, especially at low X-ray doses. Power consumption is another significant advantage of the AS5911. Its power consumption is lower than existing products on the market, with only 1.25mW per channel in low power mode. Its low power consumption will enable CT scanner manufacturers to implement temperature stabilization strategies, ultimately improving system performance and hopefully saving on thermal management costs.

     Smaller and less space-intensive than today's common CT detection-specific ADC products, the AS5911 can be integrated into detectors of all sizes, including a four-sided splicable solution, thanks to reduced external bill of Materials (BOM) and embedded components. The AS5911 reduces system complexity by integrating LDO regulators, reference voltage, temperature sensors, power decoupling capacitors, and on-chip calibration capabilities.

     Josef Pertl, senior product manager for Medical Imaging at Ams, said: "The AS5911 offers a comprehensive advantage in the field of ADCs dedicated to today's high-end CT detectors, with smaller size, lower power consumption, higher performance and integration, making it easier for system designers to use. Device manufacturers can use the AS5911 to reduce the complexity of CT detector modules in multiple sizes, including four-sided spliced CT detectors. It provides excellent power-to-noise performance and helps the next generation of CT scanners achieve higher image quality. This will help medical professionals make the right diagnosis and ultimately lead to better outcomes for patients."