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LMT87-Q1: What if the capacitive load greater than 1100pF

Eden Tsai
Prodigy 20 points
Part Number: LMT87-Q1

Hi,

In LMT87-Q1 datasheet, Figure 10 shows the capacitive load(Cload) should be less than or equal to 1100pF.
But If the capacitive load greater than 1100pF(for example: 0.022uF) without a series resistor , What will be the impact??
or side effect??

thank you

Eden

  • 0
    TI__Expert 3640 points

    Hi Eden,

    Thanks for posting to our sensing forum.

    We recommend adding a series resistor on the output of the LMT87-Q1 when driving larger capacitive loads for stability purposes. If you drive a capacitive load larger than 1100pF without a series resistor, you may see instability on your output.

    Table 4 in the datasheet provides recommended resistor values for different capacitive loads.

    Best regards,

    Jesse

  • 0 in reply to Jesse Baker
    Prodigy 20 points

    Hi Jesse,
    Thanks for your reply.
    Unfortunately, our design is firmed and cannot be changed, that's why I'm asking the impact.
    I would like to know what kind of instability of the output will occur? ripple? or accuracy?

    thank you

    Eden

  • +1 in reply to Eden Tsai
    TI__Expert 3640 points

    Hi Eden,

    We would expect to see ripple on the output due to the large capacitive load without a series resistor, which would in turn impact the accuracy of the Vout reading that corresponds to temperature.

    You could examine Vout on your current design to see if the amount of ripple is acceptable, but the series resistor values recommended in the datasheet are based on what was seen during test and validation.

    Best regards,

    Jesse