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PGA280: Schottky diode spec

Ryuuichi machida
Guru 13170 points

Part Number: PGA280

Hi,

I would like you to cofirm about below.

* Which schottky diode should be selected ?

According to datasheet of PGA280, there is following description.

VSN is connected to the substrate; therefore, the voltage at VSON or DGND must not turn on the substrate
diode to VSN. Use external Schottky diodes from VSON to VSN and from DGND to VSN (refer to Figure 50) to
prevent such a condition.

So, I believe user need to implement schottky diode. However, there is no description about required spec of this schottly diode.

How many current pulse(or continuous current) will cause ?

Or, if you have recommended schottky diode, could you please let me know ?

Best regards,

  • 0
    TI__Genius 17900 points
    Hi Machida-san,
    This schottky diode should be sized to handle any fault current present during device power-up. Unless there is a significant load on VSN or VSON, you can probably use a general purpose schottky diode like a BAT54, which should be able to handle currents up to ~200mA.
  • 0 in reply to Alex Davis
    Guru 13170 points

    Hi Alex-san,

    Thank you for your reply.

    >Unless there is a significant load on VSN or VSON

    How many load current do you assume as "significant load" ?

    According to datasheet, this device have capability to output up to 25mA current (In worst case, 7mA).

    Best regards,

  • 0 in reply to Ryuuichi machida
    TI__Genius 17900 points
    Hi Machida-san,
    This load current would be caused by any other devices on the VSN or VSON nets which might have to be powered during that power-up transient. As long as this is less than the 200mA rated current of a BAT54, it shouldn't be an issue.