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LM319-N: Can be this part used as Voltage follower?

Ricardo Cabrera Orozco
Prodigy 10 points
Part Number: LM319-N
Other Parts Discussed in Thread: LM339, LM392

I'm making a new design but I've never used this part as voltage follower, frequently I used another part numbers as buffers (voltage followers); but in this case I'm using the LM319 to compare voltages, but I need a voltage follower too, and I'd like to know if this part can be used as voltage follower to avoid use another different part number. Thank you for your fast response.

  • 0
    TI__Guru 52486 points

    Hello Ricardo,

    Actually, comparators can be turned into very poor amplifiers with NO output current drive,  limited bandwidth, horrible distortion and high offset voltage. If that sounds good to you...then, yes, you can... But you will need to add several external components.

    An example is shown in Application Note AN-74, section 21 (page 25):

    http://www.ti.com/lit/an/snoa654a/snoa654a.pdf

    Though this is for the LM339, the concept is the same.

    In brief, you add a large cap to the output and "PWM" the comparator output to charge the capacitor to create the "linear" output, then add the feedback network around that. The "output" is the stored voltage across the capacitor.

    So, yes, it is possible, but you are better-off with a "real" buffer. We do have some "combo" op-amp and comparator devices, such as the LM392.