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TPS27081A: TPS27081 Load Switch Leakage Voltage Issue

kerr chang
Genius 4075 points
Part Number: TPS27081A
Other Parts Discussed in Thread: TPS22918

Hi team

   Could you help check this issue ? 

 

Turn On the DC3V3_RF_PWR_3, UN4 TPS27081 Load Switch will have the Leakage Voltage on the    

Output DC_3V3 without the EN control.

DC3V3 Load Switch TPS27081 Leakage Voltage Issue

We have remove RN54 , DC_3V3 is 0V


  • 0
    TI__Genius 10855 points

    Hi Kerr Chang, 

    Thanks for reaching out on E2E!

    Can you elaborate on "TPS27081 Load Switch will have the Leakage Voltage on the Output DC_3V3 without the EN control." Are you saying, with the enable pin on the TPS27081 low, there is voltage on the output of the DC/DC?

    Can you share more of the schematic? What is controlling the enable pin? Can you provide a scope shot including the enable pin?

    Thanks,

    Arthur Huang

  • 0 in reply to Alpha H
    Genius 4075 points

    Hi Arthur

               Yes , The Vin(pin 4)  =3.3V and EN = Low (0V) 

                         but Vout(Pin 5) have 2.5V 7384.Doc1.docx

              Please check Attachment file.

  • 0 in reply to kerr chang
    Genius 4075 points

    Hi Arthur

              Did you have any updata ? We need fixed this issue

  • 0 in reply to kerr chang
    TI__Genius 15710 points

    Hi Kerr Chang,

    Thank you for providing the additional waveforms. On this load switch, because it is only a PMOS + NMOS, it will be susceptible to the output coming up when the input is applied. The reason is because the capacitor that controls the timing also slows down the charge and discharge of the PMOS gate. Therefore, when the input is applied, it takes time for the PMOS gate to be pulled high (OFF), and during this time, the PMOS allows current to flow from IN to OUT.

    For more information on the specifics of this event, you can take a look at section 4.2 in this application note.

    If this behavior cannot be tolerated, then I would look for a more integrated solution, such as the TPS22918.

    Let me know if you have any additional questions.

    Thanks,

    Alek Kaknevicius