128 CSAs with Triggers, Address and Sample-and-Hold Output

The IDE4184 is an application specific integrated circuit (ASIC), which has been designed for the readout of CdTe/CZT radiation detectors. The chip can be used for single photon spectroscopy of x-rays and γ-rays with energy between 20keV and 650keV and rate up to 92 kHz per chip. The chip contains 128 low-noise pre-amplifiers (130e ENC) each followed by a pulse shaper (adjustable peaking times from 0.35μs to 1μs) and a level comparator for triggering and address encoding. The amplifiers are optimized for negative polarity input charge up to -25fC maximum. When a charge from the detector exceeds one of the adjustable thresholds, the chip generates a trigger signal and delivers an analog signal proportional to the energy of the photon and an address corresponding to the triggering channel. The chip requires positive and negative voltage supplies (+1.5V and -2V) and one reference bias current to generate its internal bias currents. The total power consumption is 90 mW maximum. The chip has a 858-bit memory register, programmable via serial interface, which allows one to set various functions, program digital-to-analogue converters (DACs), and tune parameters. Each channel has an optional current compensation for detector leakage currents. All amplifier inputs are protected by diodes against over-voltage and electro-static discharge (ESD).

Keywords: Gamma spectroscopy, imaging

Product Features

DetectorsCZT, CdTe
ApplicationCalorimetry, Imaging, Spectoscopy
Number of inputs128
Input charge range0 fC to -25 fC
Shaping time0.35 μs to 1 µs
Nominal capacitive load240 pF
Equivalent Noise Charge (ENC)130e (typical)
Trigger thresholdAdjustable and programmable by 4 bit DAC
Trigger outputsAdress of triggered channel, multi-hit trigger
OutputsMultiplexed pulse height
Test and calibrationInternal calibration circuit