TPS55165-Q1: VOS_FB and PG

Shinji Tsuji

Part Number: TPS55165-Q1

Hi team,

1. Is there internal pull up or pull down in PG pin?

2. I plan to use TPS55165-Q1 at 5V setting (VOS_FB=GND). If VOS_FB pin open failure happen, how does TPS55165-Q1 behaves?

- Is there internal pull down to keep output 5V?

- Is there internal pull up which potentially increase output 12V?

- Output unregulated?

- Output shutdown?

regards,

+1 Jasper Li over 4 years ago

Hi Shinji,

there is no pull up in PG pin. there is a MOSFET to pull down

please refer to https://www.ti.com/lit/fs/slvaex6/slvaex6.pdf to understand the behavior of pins open/short.

0 Shinji Tsuji over 4 years ago in reply to Jasper Li

Hi Jasper,

For VOS_FB, slvaex6.pdf describes its failure Effect Class of "C" which is "No device damage, but performance degradation."

This pin is used to set the output voltage and I plan to set it 5V for the downstream 5V MCU.

I concern if VOS_FB pin open condition potentially set the output voltage = 12V which cause MCU to damage.

Could you clarify if it doesn't go above 5V?

regards,

0 Jasper Li over 4 years ago in reply to Shinji Tsuji

Hi Shinji,

the output voltage will be 5V if there is no voltage in this pin. typically the pin voltage is zero if it is floating

0 Shinji Tsuji over 4 years ago in reply to Jasper Li

Hi Jasper,

I understand that VOS_FB floating might cause VOUT either 5V or 12V.

regards,

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