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LM675: vs LM1875; what's the difference?

Part Number: LM675
Other Parts Discussed in Thread: LM1875,

Hi TI,

I was planning to use the LM675T to drive a low impedance inductive load.  +/- 12V supplies, +/- 0.5A from DC-10kHz where my primary concern is very high signal fidelity: low THD and low crossover distortion.  I found the datasheet of the LM1875T and it seems that the two chips are extremely similar, but whatever the differences are is not totally clear to me from the datasheet.  Could someone describe the most significant differences between the two models and advise which one might work better for this application?

Thanks,

DR

  • Hi Dominic,

    The dies are slightly different, but they are essentially the same core device. The LM1875 was originally designed as an audio power amplifier, then was "spun" as a "power op-amp" as the LM675.

    The main difference is how the two are tested in production.

    The LM675 DC specs are tighter (offset, gain, etc) than the LM1875, since Audio applications are generally AC coupled and do not care much about DC offset.

    If the application is not DC critical, they are pretty much interchangeable.

    Regards,

  • Awesome, thank you. A brief look at the internal schematics showed some differences in the input stage and the output stage with the middle gain stage looking about the same. Despite these differences the T.H.D. vs Power output graphs appear identical between the two. Is it fair to say that their expected distortion performance would be similar but perhaps the 1875 is just characterized more thoroughly for it? For example, the LM1875 datasheet includes THD vs Frequency where the LM675's doesn't.