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AS5850A

General Description

Short Datasheet

• PUBLIC

DS001024

• v2-00 • 2021-Apr-29

9

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General Description

The AS5850A is a 16 bit, 256-channel low-noise charge-to-digital converter designed for digital X-ray

systems. It enables a wide range of applications for digital X-ray including static and dynamic Flat

Panel Detectors (FPDs) used in radiographic imaging, digital mammography and high-speed

fluoroscopy.

The AS5850 device consists of 256 analog Charge Sensitive Amplifiers (CSA) with a programmable

full-scale range, a Correlated Double Sampler (CDS) for offset compensation with programmable time

constant and 128 multiplexed Analog-to-Digital Converters (ADC) for the digital readout of each pixel.

The device can be configured for electrons and holes polarity and includes a voltage reference and a

temperature sensor. Built-in diagnostic modes enable error detection in the signal chain.

The converted channels are output on a single LVDS interface with a data rate up to 320 Mbps for

optimized line time. The serial SPI interface allows the configuration of the analog frontend including

timing and different power modes for low stand-by power consumptions and fast startup times.

The AS5850 device is a high-speed design optimized for line times down to 20 µs. In a special low-

OSR (the ADC OverSampling Ratio) mode, it can reach even shorter line times of 15 µs. Additionally,

it is possible to bin together adjacent channels; with this binning, the fastest achievable line time is

10 µs.

AS5850A is the AS5850 chip delivered on a Chip-on-Flex package (A-type Flex) to minimize sidewall

distances and allow direct assembly on the X-Ray panel. Chapter 2 lists also other alternative delivery

forms. Additionally, the Flex design can be customized according to customer requirements upon

request.

1.1

Key Benefits & Features

The benefits and features of AS5850A, 16-Bit 256-Channel Low Noise Charge-to-Digital Converter are

listed below:

Figure 1:

Added Value of Using AS5850A

Benefits

Features

256 Channels with 16-bit resolution

Flexible and simple configuration via SPI interface

supporting daisy-chaining multiple devices

Ultra-low noise down to 500 electrons at 2 pC

input range for hole and electron integration

Standard and customized flex delivery down to

60 µm pitch on the high-density side

Low power dissipation down to 1.1 mW per

channel at 80 µs line time

Different power-down modes down to 1 µW per

channel and fast start-up times