A LOW-POWER HIGH-GAIN TRANSRESISTANCE BICMOS PULSE-AMPLIFIER FOR CAPACITIVE DETECTOR READOUT

A low-power, high-gain amplifier for detector readout is discussed. Th e amplifier is balanced, fully differential in circuit topology, and s ymmetrical in layout, making it radiation tolerant and relatively inse nsitive to varying magnetic fields in the large detector. Before irrad iation, the circuit has a measured differential gain of 110 mV/4 fC, a n average 10/90% rise time t(10/90%) of 19 ns, a noise figure of 433 c ircle plus 93.(C-t)(1.08 1) electrons, e(-), and a power consumption o f 750 mu W. To keep the core amplifier stable, a low-power super-low g ain-bandwidth (SL-GBW) amplifier with a small area is used and also di scussed. The SL-GBW amplifier has a transition frequency f(T) of 38 kH z (including the gain stage, A), a power consumption of 150 nW, a phas e margin (PM) of approximate to 70 degrees, an area of 300 x 36 mu m(2 ), and a minimum current per transistor of 7 nA, which is far above th e leakage current after irradiation. The complete circuit was implemen ted in the radiation hard SOI-SLMOX BiCMOS-PJFET technology of DMILL.