Charge Amplifier

  • Input File

    Charge Amplifier: SchematicCharge 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 AnalysisAC Analysis

Transient Analysis - step responseTransient Analysis - step response