TPS3703-Q1: Issue with reset release

N Shrinidhi Bhat

Part Number: TPS3703-Q1

Hello,

Support requested for understanding the issue.

We have used the chip TPS3703B4250DSERQ1 in our design. While testing the board, we have encountered the issue that the reset is not releasing. 5V power line is stable.

Design parameters:

5V0_PREREG_SOM2: 5V measured

SOM2_Manual_Reset: 5V(measured continuous 5V on this line)

SOM2_PWR_EN: 0V measured --> expected 5V here but the chip is pulling down the signal(even after removing R84).

Wondering what could be the problem here. Could it be timing issue?

over 1 year ago

0 Jesse Villanueva over 1 year ago

TI__Mastermind 18690 points

Hi Shrinidhi,

Could you please provide a scope shot of the SENSE pin node, SOM2_PWR_EN and MR.

This should help with troubleshooting.

Jesse

0 N Shrinidhi Bhat over 1 year ago in reply to Jesse Villanueva

Prodigy 30 points

+1 Jesse Villanueva over 1 year ago in reply to N Shrinidhi Bhat

TI__Mastermind 18690 points

Hi Shrinidhi,

Based on the the image you have provided, it looks like the Vsense voltage is on the lower edge of the under voltage detection window. With the device PN you have, it is a 4% window tolerance with 2.6V for over voltage threshold and 2.4V under voltage threshold. For testing purposes, could you please switch the R75 to a 9.5kohm resistor to slightly bring up the Vsense voltage.

Jesse

+1 N Shrinidhi Bhat over 1 year ago in reply to Jesse Villanueva

Prodigy 30 points

Hello,

As you suspected the Vsense pin, I varied the voltage on Vsense pin from 0V to 5V. Reset triggered at ~810mV, wrong part was mounted by vendor.

Mounted part was TPS3703A4085DSERQ1.

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TPS3703-Q1: Issue with reset release