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LMT84: 1000nF Capacitive Loading Restrctions?

Filipe Rubinstein
Intellectual 811 points
Part Number: LMT84

Hi All, 

I am investigating the LMT84's ability to handle capacitive loads as shown in section 8.4..3 of the datasheet below. However, I have some questions regarding Table 4 below. According to the table, from 100nF to 999nF I should use a 1.5kohm resistor, but 1000nF I should use a 800ohm resistor. The 999nF to 1000nF jump is what sticks out to me. 

I would like to know if it is okay for me to continue using a 1.5kohm series resistor value even if my capacitance hovers around but may not exactly be 1000nF. 

Is there an equation that is used/available for calculating the series resistance needed?

Thank you,

Filipe

  • 0
    TI__Expert 6295 points

    Hi Filipe,

    What this table depicts is that for 1uF capacitive loads or higher, you should use at least an 800 ohm series R. Keep in mind that a 1uF is fairly large and I would advise looking into solving the large capacitance issue. In terms of equations, the main drive here is the pole of the amplifier output of the device to maintain the output stable. Please let me know if more detail is needed, thank you.

    Best regards,

    Simon Rojas