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Understand the working of OPA2810 as a buffer

Rajat Jhunjhunwala
Prodigy 110 points

Part Number: OPA2810IDGKR

Hi TI,

We are looking for an alternate to OPA2863. We came across OPA2810 which has required slew rate and package with pin to pin matching. 

What my query is how is it different from OPA2863. Can I use it as a buffer for a window comparator where the latch time is less than 100nS? Will the internal architecture be a hurdle in this?

My input is square wave in the range (+1V to +5V). 

 

  • 0
    TI__Expert 8750 points

    Hi Rajat, the OPA2810 is a JFET amplifier, which gives it high DC input impedance, and it is a 28V device. OPA2863 is a BJT amplifier that has a little more bandwidth, a little less noise, and half of the voltage range. It is also less expensive. OPA2810 will draw 5x the quiescent current of the OPA2863.

    From a performance standpoint, OPA2810 will have double the slew rate vs. OPA2863. If that is a critical parameter, another part to look at would be OPA817 (10x slew rate), but it is a different package.

    What is your concern about "internal architecture" specifically? These are both crossover type devices, and the THD will be lower if you confine operation to a sub-interval of the full voltage range.

    Best regards,

    Sean

  • 0
    Guru 140180 points

    Hi Rajat,

    for highest speed it's recommended to not drive the input and output of OPAmp into saturation. I would add a voltage divider at the input to guarantee that the output voltage is always 0.2V away from the supply rails.

    Kai

  • 0 in reply to kai klaas69
    Prodigy 110 points

    The input varies from 1.2V to 3.8V.

  • 0 in reply to Rajat Jhunjhunwala
    Guru 140180 points

    Hi Rajat,

    Rajat Jhunjhunwala said:
    The input varies from 1.2V to 3.8V.

    This is good to know. You earlier said:

    Rajat Jhunjhunwala said:
    My input is square wave in the range (+1V to +5V). 

    Kai