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TPS84259 PH pin Absolute Maximum Rating

Other Parts Discussed in Thread: TPS84259

Hi

My customer has a question about TPS84259.
Could you tell me about question?

[Question]
 My customer has question about PH rating. In datasheet, PH voltage rating is referenced to GND.
 But my customer is thinking, PH voltage rating is referenced to A_Vout. Because when FET turn-on, PH voltage is close to VIN and when FET turn-off, PH voltage is close to Vout.
 If datasheet is correct, when FET turn-off, PH voltage is close to Vout. That’s mean PH rating is over in some cases.
 Could you tell me about PH rating.

Best regards,

tateo

  • Hi Tateo,

    Great question.  The max. PH voltage rating 45V, as in the datasheet, was referred to GND.  The max. PH voltage rating, if referred to A_Vout, was over 60V.  Since the max. Vout (same level as A_Vout) for this part was -17V, the total PH voltage to A_Vout would be 62V, which was still over the spec.

    Hope this help.

    Best regards,

    Hung

  • Thank you for your help. When Vin=24V, Vout=-12V, PH voltage is referenced to GND is -12 - Vf V to 24V. If Datasheet is correct, we can't use this device in this case.
    But If PH voltage is referenced to A_Vout, PH voltage is -Vf to 36V. We can use this device. Could you tell me about PH rating?

    Best regards,

    tateo

  • I'm sorry to rush you but we would appreciate it very much if you could tell us about PH rating.

    Best regards,

    tateo

  • Hi Tateo,

     

    Sorry that you did not get the response.  I must reply to the email notification, instead of the forum directly.

     

    Hung

     

    ------------------------------------------------------------------------------------------------------------

    From: Hung, Ching-Yao
    Sent: Wednesday, February 18, 2015 8:17 AM
    To: TI E2E Community - Automated Email
    Subject: Re: Power Modules - Forum: TPS84259 PH pin Absolute Maximum Rating

     

    Hi Tateo,

     

    The voltage rating in the datasheet are always referred to GND, unless else stated.  The absolute max PH voltage, as referred to GND, was 45V.

     

    If referred to A_OUT, the max PH voltage rating would be 65V.

     

    Please send me an email at chung@ti.com if you have any further question.

     

    Thanks,

     

    Hung