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TPS7A89 Safe Operating Area

Moham
Intellectual 635 points
Other Parts Discussed in Thread: TPS7A89, TPS7A84

Hi,

I'm searching a linear regulator for the best output noise, PSRR and thermal performance for powering 1.15V@ 0.9A ADC. During search i found TPS7A89 TI LDO. My input voltage can be applied to regulator is 2.35V and i guarantee ambient temperature to maximum 60 degreeC. My question is that according to figures of page 32 of related datasheet can i use TPS7A89 without risk and if required conditions and considerations exist, highlight them for me. If there is risks like thermal boundary, extra output noise, ... using TPS7A89 in this config or there's a better solution, please inform me.

Regards

  • 0
    TI__Expert 7035 points

    Hi Moham,

    This section of the datasheet is there to describe the operating characteristics of the device. As mentioned on page 31 of the datasheet there are 4 limitations to continuous operation. In your case you only need to be concerned with two of them. The drop out performance and the thermal regulation. The max dropout voltage of the device is 400mV and you have 1.2V of head room so you are fine there. The other consideration is thermal performance, you will be dissipating 1.08W in the device, which corresponds to a rise in temperature of 35.64C. If your max ambient is only 60C the part should not enter thermal shutdown as that does not kick in until 140C. There are other solutions with similar noise performance such as the TPS7A84, which is only a single output that would also work for your application.

    Best Regards,

    Mark

  • 0 in reply to Mark Sellers
    Intellectual 635 points
    Mark,

    Thanks for your perfect answer and part suggestion, so can i extrapolate provided recommended operating areas? And finally is mentioned conditions sufficient for guaranteed work of this regulator?

    Best Regards,

    Moham
  • 0 in reply to Moham
    TI__Expert 7035 points
    Hi Moham,

    You should be able to extrapolate the safe operating areas from these curves. The regulator should work at your mentioned conditions as you are providing sufficient headroom and are not dissipating enough power to put it in thermal shutdown.

    Best Regards,
    Mark