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LM5050-1-Q1: LM5050 PIN abs rating

Hollis Liu
Intellectual 2535 points
Part Number: LM5050-1-Q1

Hi team,

i would like to konw why the min IN/OUT pins to Ground voltage is -0.3V in datasheet 6.1 Absolute Maximum Ratings. 

Is it related to the internal protection circuirt? If so, can you share me a common circuit of Pin protection? Thanks. 

  • 0
    TI__Genius 16305 points

    Hello Hollis Liu,

    Absolute minimum voltage on IN/OUT pins is -0.3V and this is due to the internal ESD protection circuit which has ESD diode from IN to GND. In fact all the LM5050 IC pins have this ESD protection and hence ESD diode from each pin to GND. These diodes are oriented with its anode connected to GND and cathode connected to IN or OUT or each other pins.

    -0.3V is the forward voltage drop limit of the diode to limit its forward current. Also note that -0.3V is the rating across full operating temperature. Especially at -40C forward voltage limits drop to -0.3V, but at 25C it can handle -0.7V. Pushing these pins below, for a long time will damage the ESD diode and leads to pin short to GND.

    Are you looking for reverse polarity protection on IN and OUT pins where these can handle large negative voltage below -0.3V?

    Regards,
    Kari.

  • 0 in reply to Karikalan Selvaraj
    TI__Genius 16305 points

    Hello Hollis Liu,

    If you need protection circuit to prevent IN/OUT pins from going below -0.3V, placing a shcottky diode from IN to GND and OUT to GND will prevent damage to the IC.

    Regards,

    Kari.

  • 0 in reply to Karikalan Selvaraj
    TI__Intellectual 2535 points

    Thanks Kari. You answered my question.