• State
  • Locked Locked
  • Replies 1 reply
  • Subscribers 63 subscribers
  • Views 474 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS3808 reset pin used to block an ac signal

Carl Haynie
Prodigy 30 points
Other Parts Discussed in Thread: TPS3808

I am considering using the TPS3808 reset pin in a non-conventional way and wonder if anyone has had experience with this idea, or who may want to steer me away from it for some reason.  The design would use the open-drain reset line as a pull-down to short an ac waveform to ground.  The signal is a nearly square wave at about 50kHz with a source impedance just above 10k Ohms.  Two possible problems are 1.  Pin capacitance may cause distortion to the signal when enabled.  2. Signal swing may cause unanticipated malfunctions inside the TPS3808.  

  • 0
    TI__Prodigy 215 points

    Hi Carl,

    You would need to keep in mind the maximum values for voltage and current for the RESET pin. Exceeding these values will damage the device. Refer to the tables in the datasheet for more details:

    If your current exceeds the maximum value, you could try adding a pull-up resistor to the drain, and connecting the output to an external PMOS to ground your ac signal.

    There will be some parasitic capacitance in the device, but these are usually so small that they should not affect your signal. Similarly, signal swing should not pose an issue, since the reset pin is just an open-drain pin.

    Regards,

    Yuanhao