LM1875: Use as an op amp

Matthew Gardner1

Part Number: LM1875

I have just recently purchased these IC to use as a cheap voltage following buffer and am requiring it to be used as a current amplifier as well. All I require the op amp to do is to source about an amp or three to drive a .1 ohm resistor for my current amplifier circuit would there be any issues to the reliability of this chip? All I am doing as the buffer is taking a 10V ac sine wave and buffering the voltage source because my source cannot handle much current. The op amp only needs to supply 30mA of ac to drive the low side of a transformer. Does this sound doable for the LM1875 with proper cooling? I accidentally already burnt one of them because I was not properly cooling it but I want to make sure that was my only issue.

over 4 years ago

0 Hector Zhang over 4 years ago

TI__Prodigy 600 points

Hi Matthew,

Please notice the LM1875 has a small bandwidth of 70kHz, you need to make sure this device is fast enough for your signals. Besides this I do not see other problem. Of course, the cooling is important. Thanks.

Regards,

Hector Zhang

0 Matthew Gardner1 over 4 years ago in reply to Hector Zhang

Prodigy 140 points

Thanks for your reply Hector,

One quick follow up question, if you are an expert on the LM1875. Its output current (Io) I'm seeing the data sheet say 4 Amps Maximum limit, I am assuming it can sink and source current both directions depending on a dual supply, is this correct?

0 Hector Zhang over 4 years ago in reply to Matthew Gardner1

TI__Prodigy 600 points

Hi Matthew,

Yes, your understanding is correct.

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LM1875: Use as an op amp