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LMG5200: rise/fall time specification

Brian Zoro
Expert 3890 points
Part Number: LMG5200

Hello all,

is there a  specification of rise/fall time for the LMG5200 on a 50Ohm load?
I could not find it in the datasheet, expect from fig.13 from which I see that the 50V are achieved in aprox. 2ns.
There is one note that says something about 50V/ns with the notificatrion "this parameter is guaranteed by design. Not tested in production".

Can anybody help me here?

Thanks in advance!
Best regards,
Brian

  • 0
    TI__Genius 16390 points

    Hello Brian,

    Thanks for contacting us. In the datasheet, the switching slew rate for turn-on is specified at maximum of 50 V/ns (in section 6.3). However, the actual turn-off slew rate might be lower due to parasitic capacitance in PCB and device variations.

    In a buck converter, the turn-off slew rate depends on the inductor current which charges the output capacitance of the FET, which is related to the load current.  Now, assume the output voltage is 50V and load is 50 ohm, the load current will be 1A. The typical output capacitance is specified to be 266 pF for LMG5200, the turn-off slew rate can be estimated to be 3.8V/ns. However, turn-on transient is a hard-switching transient which does not rely on load. As mentioned in the datasheet, the max. slew rate is 50V/ns. Typically it varies between 40V/ns to 50V/ns.

    Regards,

    Yichi Zhang

  • 0 in reply to Yichi Zhang.
    TI__Expert 3890 points

    Hello Zhang,

    many thanks for explanation!

    best reagards,
    Brian