TRS3232ECPW issue

Patrick Chen

Mastermind 8875 points

Other Parts Discussed in Thread: TRS3232

Hello,

he schematics of customer is as below.

Condition : PC RS232-TX to pin13 RIN1 ->pin12 ROUT1 to MCU UART-RX

±10V -> 0~3.3V inverting signal

After long time test

The voltage is changed to 3.3V -> 3.3V non-inverting signal and function abnormal.

What is the issue root cause for above phenomenon？ Thank you.

Patrick

over 9 years ago

0 ShreyasRao over 9 years ago

TI__Guru 61970 points

Hi Patrick ,
I have contacted the appropriate apps engineer on your query .

0 Ron Michallick over 9 years ago

TI__Guru**** 164656 points

Patrick,

Which voltage changed to 3.3V?

0 Patrick Chen over 9 years ago in reply to Ron Michallick

Mastermind 8875 points

Hello Ron,

+- 10V will be changed to 3.3V. Thank you.

Patrick

0 Ron Michallick over 9 years ago in reply to Patrick Chen

TI__Guru**** 164656 points

Patrick,

+3.3V on a receiver input should result in the ROUT being low.
Was it observed as ROUT high?

0 Patrick Chen over 9 years ago in reply to Ron Michallick

Mastermind 8875 points

Hello Ronald ,

No, the phenomenon observe on Pin13 and Pin8 R1IN/R2IN. The +- 10V voltage of Pin13/Pin8 will be changed to 3.3V. But after power on, the phenomenon will be recover to normal. Thank you.

Patrick

0 Ron Michallick over 9 years ago in reply to Patrick Chen

TI__Guru**** 164656 points

Patrick,

I read that as 'RIN voltage change was not a done on purpose and the TRS3232 is suspected of shorting those to line to the 3.3V supply.
I didn't jump to that interpretation because I can't think of any reason for that to happen internal to the device.
The RIN inputs have 5.3k to ground then pass through 100k so internal shorts to VCC pin doesn't make sense.

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TRS3232ECPW issue