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  1. #1
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    More current from multi channel opamp buffer

    Would ganging all channels of an LM324 to buffer +/-5v from a dual supply ~25mA per channel cause its high frequency performance to drop? There are specialty buffer opamps but I only need =<1Mhz. This is to measure parasitics of coils and transformers.

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  2. #2
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    Re: More current from multi channel opamp buffer

    Consider that paralleled OPs will work against each other due to input offsets, drawing excessive current form the power supply.


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  3. #3
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    Re: More current from multi channel opamp buffer

    Agree but shouldn't be too hard to fix. 1 ohm balancing resistor means 1mA current imbalance assuming 1mV offset while adding 20mV output voltage variation over 20mA load. Maybe that's fine?

    Or gang together 3 opamps with balancing resistors and use the 4th opamp to regulate their output (cascade costs some bandwidth).

    But yes, buying an appropriate buffer amplifier may be the best choice. Be careful with opamp current specs too, many specify typical output current, not minimum.



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