A Low Noise 32-Channel CMOS Read-Out Circuit for X-ray Silicon Drift Chamber Detectors

Abstract

In this paper we present a 32-channel integrated front-end circuit for low-energy (0.5–100 keV) X-ray detection with a multi-anode silicon drift detector. The front-end circuit includes 32 read-out pixel cells (RPC), each consisting of a low noise preamplifier, a second-order RC-CR pulse shaper, a peak stretcher, an amplitude and a peak discriminator, as well as a reset and pile-up rejection circuit. Most of the parameters of the front-end circuit are programmable through a digital configuration register, supporting daisy-chain connection. At room temperature the equivalent noise charge of the RPC is 18.3 e^? and its linearity error is lower than 5% over the complete input range. The front-end circuit has been designed in a 0.35-?m CMOS technology with main 3.3-V power supply. A single RPC occupies an area of 200 × 380 ?m² and consumes 0.4 mW.