OP-AMP Selection

Discussion in 'The Projects Forum' started by emblem, Jul 31, 2008.

  1. emblem

    Thread Starter New Member

    Jul 31, 2008
    1
    0
    I want to drive a resistive load using the output of a DAC attached to a PC. The load is approx. 500 ohms driven over a voltage range of -5 to 5 volts, or 10mA maximum current sink/source. Sadly, my DAC is only good up to 5mA. I'd planned to use an opamp as a buffer to drive the load, but am having trouble selecting a particular model. I'd like to find a 14-DIP package with the standard pinout for a quad op-amp. Most of the spec sheets I've looked at show big drops in maximum output voltage when the output currents approach 10mA. I'd rather not build a push-pull output stage, although that would solve the problem. The LT1010 seems like it might do the trick, but it's the wrong package and pinout.

    Any suggestions?
     
  2. scubasteve_911

    Senior Member

    Dec 27, 2007
    1,202
    1
    You just need an non-inverting voltage follower to buffer the signal. Ensure there is 'rail-to-rail' input and output and that it can supply the 10mA. Also, consider other parameters such as gbw, input offset, noise density, if you want it to well well.

    Steve

    just a quick find, this is almost good enough OPA743, but has about 300mV from rail. You just need to look around a bit until you find something. Or, power from +/- 6V instead.
     
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