A low-power variable-gain front-end amplifier in a 0.25 (mu)m CMOS technology

This paper describes a front-end amplifier whose gain and shaping time are programmable. The circuit employs a two-stage architecture and has a secondorder shaping function. The tunability of the amplifier is obtained by mean of CMOS switches that set the value of the passive components used in the feedback loop of the second stage. The shaping time can be changed from 30 ns to 130 ns and the gain from 10 mV/fC to 80 mV/fC. Fabricated in a 0.25 (mu)m CMOS technology, the circuit occupies an area of 0.1 mm/sup 2/, and dissipates a power of 2 mW from a 2.5 V supply.