1 Features

1• 256 Channels

• On-Chip, 16-Bit ADC

• Photodiode Short Immunity

• Column Short Immunity

• High Performance:

– Noise: 758 e-RMS with 28-pF Sensor

Capacitor in 1.2-pC Range

– Integral Nonlinearity:

±2 LSB with Internal 16-Bit ADC

– Minimum Scan Time:

– 37.9 μs in Normal Mode

– 20 μs in 2x Binning Mode

• Integration:

– Eight Selectable Full-Scale Ranges:

0.15 pC (Min) to 9.6 pC (Max)

– Built-In Correlated Double Sampler

– 2x Binning (Averages Charge of Two Adjacent

Channels) for Faster Throughput

– Pipelined Integrate and Read: Allows Data

Read During Integration

• Flexibility:

– Electron and Hole Integration

• Low Power:

– 2.9 mW/Ch with ADC

– 2.3 mW/Ch without ADC

– 0.1 mW/Ch in Nap Mode

– Total Power-Down Feature

• 22-mm × 5-mm Gold-Bump Die,

Suitable for TCP and COF

2 Application

Flat-Panel, X-Ray Detector

3 Description

The AFE1256 is a 256-channel, analog front-end

(AFE) designed to suit the requirements of flat-panel

detectors (FPDs) based on digital X-ray systems. The

device includes 256 integrators, a programmable gain

amplifier (PGA) for full-scale, charge-level selection, a

correlated double sampler (CDS) with dual banking,

256:4 analog multiplexers, and four 16-bit,

successive-approximation register (SAR) analog-todigital

converters (ADCs) onboard. Serial data from

the ADCs are available in SPI™ format.

Hardware-selectable integration polarity allows for the

integration of positive or negative charge and

provides more flexibility in system design. The Nap

feature enables substantial power saving. This power

savings is especially useful in battery-powered

systems.

The device is available as a 22-mm × 5-mm goldbumped

die and a 38-mm × 28-mm, COF-314 TDS

package in singulated forms.

To request a full data sheet or other design

resources: request AFE1256