ams AS5911 CT 检测器接口

Dragster是一款数字线行扫描传感器，分单线双线两种设计方式：单线系列，像素尺寸为7µm×7µm或3.5µm×3.5µm；双线系列，提供单色和彩色两种选择，像素尺寸为7µm×7µm。传感器的读取由两个12位宽数字tap组成，每个2k段按奇/偶顺序排列。对于每个线段，所有的2k像素点都采用相同的读取方法。对于像素点间距为3.5μm的传感器版本，安装在像素线的两侧的两个读取电路形成一个4k像素点的基本段，其中偶数像素点通过底部读取电路读取，奇数像素点通过顶部读取电路读取。

The AS5912 is an ultra-low noise, 512-channel low power current to digital converter that enables the readout of photodiodes of a CT detector with highest sensitivity. The output currents of 512 photodiodes are converted simultaneously into digital without any dead time resulting in no charge loss on the inputs. The AS5912 combines current-to-voltage integration and A/D conversion for 512-channels in one device. The ADC architecture with its low-noise integrators, coarse quantizer, sample-and-hold and fine quantizer guarantee lowest input related noise of maximum 0.29 fC (low noise mode) at an input current range of 0.5 µA. The input current range of the ADC is selectable between 0.5 µA and 1 µA.The AS5912 supports two supply concepts: a single analog and true ground supply, in both modes the photodiodes are zero biased for ultra-low dark current of the photodiode. In true ground mode, the AS5912 operates at ±1.5 V dual analog supply while in single supply mode only a single analog supply of +3.0 V is needed. The device detects automatically the chosen supply concept. No external components are required for supply decoupling. To reduce PCB area and simplify the assembly process, decoupling capacitors for supply and reference voltages are integrated in the 23 x 15 mm² FBGA package. The on-chip LDOs, reference voltages and a temperature sensor minimize the external component requirements and reduces the bill of material.Full-scale range, integration time and power mode are configurable over a SPI-compatible serial interface as well as the digital output modes of the LVDS interface. In low power mode, the power dissipation can be minimized down to 1.25 mW per channel for reduced self-heating of the CT detector. The adjustable integration time down to 51 µs allow very high frame rates.