LMV794 amplifier design...

Discussion in 'The Projects Forum' started by cool_buddy, Aug 7, 2014.

  1. cool_buddy

    Thread Starter New Member

    Aug 7, 2014
    I m using LMV794 as amplifier circuit for photodiode BPW34S.In first stage i put 5.6M resistor and 10Pf.The supply voltage is 3.3v.The first stage output is around 1.5-1.7v.In second stage one input is 0.9v dc and other is the output from first stage.I used 6.8k resistor to obtain 2v finally.But my waveform is like spikes.i dunno wat capacitor value sud be put? I need rectangular pulse... pl sumone help how to calculate both feedback resistor and capacitor.The frequency used is 4khz...
  2. crutschow


    Mar 14, 2008
    There's no DC path for the photodiode current. You need a high value resistor from the photodiode's anode to ground.