Charge Amplifier

• Input File

  Charge Amplifier: Schematic

  .title High Impedance Charge Amplifier
  ' 12 intervals per decade, from 1. to 5.KHz
  .ac 1.0 5.kHz 12 10
  ' transient (step) response, 0. to 10. msec
  .tr 200 0. 10.msec
  ' pull in an op-amp model
  ' lmc6022 low power cmos op amp
  .include /usr/local/lib/ccicap/lmc6022.mdl
  ' plot output as a png graphic
  .plot ac png eout eout >
  .plot tr png eout
  ' circuit description
  .ckt
  ' input signal source
  v ein 1 2 1.0
  ' input capacitor
  c ch 2 3 350.p
  oa a1 1 3 4 6022
  ' feedback capacitor
  c cf 4 3 700.p
  'feedback resistor
  r rf 4 3 22.M
  ' capacitor to gound
  c cg 1 0 700.p
  ' resistor to ground
  r rg 1 0 22.M
  ' output LP filter
  r rout 4 5 1.k
  c cout 5 0 .33u
  ' measure output at node 5
  vm eout 5 0
  .end
  .go
  ' expand the analysis range
  .ac 0.01 10.k 8 10
  ' redo plots
  .plot clr
  ' cancel transient response
  .tr clr
  ' add noise analysis
  .noise
  ' look at noise density and integrated noise
  .plot ac png NDM INM
  ' create a noise table of integrated noise
  .n_table inte 8
  .go
  .stop
  

The AC and Transient Plots are available here:
AC Analysis

Transient Analysis - step response