TPS54335A: PH issue

T Kishi

Part Number: TPS54335A

My customer has question.

The usage conditions are as follows.

VIN = 27 V
Vout = 5V
IOUT = 40 mA

When used under the above conditions, a phenomenon occurs in which the resistance value between PH and GND decreases (about 5 Ω).
I saw this article, is the same phenomenon occurring?

https://e2e.ti.com/support/power-management/f/196/t/745780?tisearch=e2e-sitesearch&keymatch=TPS54335A

https://e2e.ti.com/support/power-management/f/196/t/789919?tisearch=e2e-sitesearch&keymatch=TPS54335A#pi320995filter=answers&pi320995scroll=false

If so, please cooperate as we would like to respond promptly.

Regard

T Kishi

over 6 years ago

0 Shawn Nie over 6 years ago

TI__Genius 10070 points

Hi,

The input voltage is 27V, there is only 1V margin. If the layout is not good, the spike voltage of SW would be very large, this may result in damage. You can test the SW waveform.

Shawn

0 T Kishi over 6 years ago in reply to Shawn Nie

Genius 4425 points

Hi Shawn

Thank you for reply.

Although there is certainly no margin, no noise such as ringing has occurred, so the maximum rating has not been exceeded.
In spite of that, the customer is considerably troubled because it is damaged.
Do you have any information?

Regard

T Kishi

0 Shawn Nie over 6 years ago in reply to T Kishi

TI__Genius 10070 points

Hi,

Could you please share the schematic and layout? Let's review them.

And I think you can test the SW waveform to check the spike voltage. When you measure the data, please set the bandwidth to 500MHz.

Shawn

0 T Kishi over 6 years ago in reply to Shawn Nie

Genius 4425 points

Hi Shawn

Thank you for reply.

Since I can not attachment it here, can I have your E-mail Address be taught?

Regard

T Kishi

0 Shawn Nie over 6 years ago in reply to T Kishi

TI__Genius 10070 points

shawn-nie@ti.com

Shawn

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TPS54335A: PH issue