FBE-ASIC microelectronics experts

ASIC Example Project: Quad CMOS Low-Noise Charge Sensitive Preamplifier

F-CSA104 contains 4 channels of charge sensitive preamplifiers with differential line drivers. It has particularly been designed for the use with semiconductor radiation detectors operating with liquid nitrogen as coolant (T = 77K/-196°C).

F-CSA104 joins the formerly discrete input FET with the preamplifier in a single IC, thus forming the next step of integ­ration for better immunity to interference. F-CSA104's noise performance has been optimized for use with capacitive detectors of 0 - 100pF; flicker noise is reduced by use of a p-channel MOSFET as input transistor. In cases where noise matching to higher capacitance detectors is vital, an external p-channel FET may be connected to the IC.

A range of F-CSA104's parameters (including offset and preamplifier decay constant) can be programmed via an I2C interface. F-CSA104's linearity and offset have been designed for use with 14 bit ADC systems, thus being ideally suited for spectroscopy applications. The high current drive differential line drivers allow for directly driving a 100 Ohm twisted pair cable.

  • Very low noise (ENC=220e- @ Cdet = 30pF, T=27°, Tpeak = 20µs)
  • Temperature range -200°C ... +50°C
  • Fast differential outputs (trise < 30 ns)
  • Gain 5.84 mV/fC, 316 mV/MeV(Ge), 258mV/MeV(Si)
  • Input signal range ± 600 fC, ± 11MeV(Ge), ± 13MeV(Si)
  • 14 bit linearity for spectroscopy applications
  • Adjustable preamplifier time constant 1us ... 1.5ms
  • Optional connection of external p-channel FET
  • Optimized for detectors of 0 pF ... 100 pF
  • All stages DC coupled, triple offset suppression
  • I2C-interface for parameter adjustment

Block diagram

Data Sheet (pdf, 173 kB)