Instr. Amp. offset control cirquit

Discussion in 'The Projects Forum' started by Crowbar, Jan 12, 2007.

  1. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
    32
    0
    Hi, need an output INA voltage adjustment in a range of few mV. I must take into consideration charge pump power supply noise and cause cirquit operates with 30mkV values- think that such scheme works, isn't it:
    [​IMG]
     
  2. Distort10n

    Active Member

    Dec 25, 2006
    429
    1
    If you are asking if the circuit from the PGA204/05 Datasheet will work to adjust offset for instrumentation amplifiers, then yes. What is the specification on the charge pump? Noise should never be induced into the reference. Easier said than done.
     
  3. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
    32
    0
    Charge pump will give ripple near 10mV into power supply rails. We can't connect 10KOhms pot directly to power supply rails cause we will have ripple affecting A3 + input in INA- that's why I asked about cirquit using REF200(it gives 100uA +/-0.2% output with max 1nA noise).
     
  4. Crowbar

    Thread Starter Active Member

    Dec 19, 2006
    32
    0
    Is it true that REF200 provides some sort of current stabilisation(when we see on simplifed cirquit diargram)?
     
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