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DAC7760: DC PSRR performance

Vladimir Aparin
Expert 2610 points

Part Number: DAC7760

Can we get graphics of dependencies of PSRR from temperature?

In datasheet provided only maximum value - 1 uA/V.

We want to use DAC7760 on 36V, so maximum value can be so high as 36 uA. That equal 0.225% of Full Scale for 4-20 mA output. It's very high value.
We want to calibrate our devices to compensate this impact. So we need this information.

  • 0
    TI__Expert 5820 points

    Hi Vladimir,

    This specification indicates how low frequency supply voltage variation will impact the output. It does not mean that for every DC volt of supply that 1uA error occurs. For instance if you had a 30V supply with 1V of low frequency ripple it would result in a ripple of 1uA on the current output. I can look to see if we can provide this over temperature if needed but I think the correct interpretation of the spec shows that there will be very little output ripple in the current if a well regulated power supply is used.

    Thanks,

    Garrett

  • 0 in reply to Garrett Satterfield
    Expert 2610 points
    Hello Garrett,
    Thank you for you answer. There are much more clear now.
    Please provide dependencies over temperature if you can. It's very interested for us.
  • 0 in reply to Vladimir Aparin
    TI__Mastermind 46290 points
    Hi Vladimir,

    Garrett is out of office on personal leave, so I am stepping in on this thread for the time being. Thank you for your patience in the transition.

    I would offer you the insight that, generally speaking, you can expect for PSRR to vary in similar orders of variation over temperature to GBW. So, typically speaking, something on the order of 25%-30%. I have seen more conservative "rules of thumb" suggesting even 50%. Personally, I believe closer to 30% based on observations in the past.

    It is very difficult to control Gm to a tight margin, so this is pretty common across many devices / manufacturers and typically not specified.

    I hope the insight is helpful for you.