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TPS54327 VFB Pin sensetive to Noise

Padmanabh Gawai
Prodigy 20 points
Other Parts Discussed in Thread: TPS54327

I am using TPS54327 DC-DC for converting 12V DC- to 5V DC. I am facing a problem that the Voltage Feedback pin of this IC is sensitive to Noise.When i touch this pin by hand the output switched OFF and the IC starts heating.After power OFF and Restarting Output is ON till you touch it.

 I have also check by having ESD wist strap if this is an ESD problem but still problem exists.

I have used the recommended Resistor and capacitor values as per datasheet and Application note. I have observed this issue on TI Evaluation Board for this chip, so I guess this is not my PCB layout issue.

I have contacted TI FAE but as per them this issue was not observed yet buy other users.

Need Help to finalize my design.

  • 0
    TI__Guru**** 191445 points

    I have heard this from time to time.  The VFB pin is high impedance.  Touching it may cause the TPS54327 to not operate properly.  Touching the device will introduce unknown stray capacitance and additional impedance to the pin.  I recommend not to touch it.  I may have additional comments later.

  • 0 in reply to JohnTucker
    Prodigy 20 points

    If i do not touch the VFB pin ,and the Output is as expected should I consider that the DC-DC controller is working well as Expected.

    Attached Schematic for DC-DC

    Please Comment,if this schematic is OK.