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LSF0108: LSF0108: Possible to drive the EN pin with a push pull device

Thanh Dang Nguyen
Prodigy 60 points
Part Number: LSF0108

I have just watched your tutorial video at: https://training.ti.com/TLM-LSF-Enable?cu=1134826

and I understand that is not possible to drive the EN pin with a push pull output like below circuit:



Unfortunately, my device only have the push pull output. I have read in LSF0108's datasheet and I think the below circuit can drive the EN pin, but I'm not sure.

1. Could you help me to confirm the below circuit can work or not?

2. If not, could you recommend me another way?

  • 0
    TI__Guru* 96591 points

    Hi Thanh,
    Yes, this circuit can be used. Here you are forcing the gate voltage on the internal nFET to 0V, which will effectively turn off all channels. As long as your device has a relatively low output impedance, there is no problem with this circuit.

    ** Correction **

    Sorry for the double post, I just realized that the primary issue here is with the discharge of the 0.1uF through the 200kohm resistor.  It will be slow -- probably taking about 0.1s to fully discharge.  I'm guessing that you really don't want to wait that long for the device to be disabled.