5V Tolerant VBUS

ali motamedi

Other Parts Discussed in Thread: TPS2051B

as i know all of TM4C129 pins are 3V tolerant except PB1 that used for VBUS monitoring. but when i connect this pin to 5V , my MCU gets warm without any change in board current. only gets warm (so hot) and after a while , some other GPIO pins not work as expected

over 10 years ago

0 Amit Ashara over 10 years ago

TI__Guru**** 244400 points

Hello Ali,

When you connect 5V to VBUS do you mean via a USB connecctor?

Regards
Amit

0 ali motamedi over 10 years ago in reply to Amit Ashara

Prodigy 120 points

Hi !
no 5V comes from pin 1 of TPS2051B. this pin (out) connects to my USB connector and PB1 of CPU. TM4C config in host mode and warm up occurs even when no mass storage inserted.

0 Amit Ashara over 10 years ago in reply to ali motamedi

TI__Guru**** 244400 points

Hello Ali,

Thanks for the information. Now without a mass storage device connected if the TM4C129 is heating up (a temp that does not allow the finger to be not kept for more than a second) it could be possible that one of the previous physical connect and disconnect has triggered the errata GPIO#09 causing a device damage.

Regards,
Amit

0 ali motamedi over 10 years ago in reply to Amit Ashara

Prodigy 120 points

thanks. you exactly hit the ace! i tested it on all my 100 boards. it seems that after an ESD discharge on PB1, this heat up begins. the only solution is to cut wire on PCB to isolate PB1 from the board and connect pin 1 of TPS2051B to USB connector directly by an external wire. i can ground PB1 and PB0 on my next designs as mentioned in errata GPIO#9 (because we only need to use USB in host mode)

0 Amit Ashara over 10 years ago in reply to ali motamedi

TI__Guru**** 244400 points

Hello Ali,

Or place the Low Pass Filter as suggested in the errata. That has helped out a lot of other users and developers.

Regards
Amit

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5V Tolerant VBUS