TRS3253E: Issue with RS-232 output drive at cold temperatures below -20C

Kent Closson

Part Number: TRS3253E

At cold temperatures both the positive and negative levels of the output signal are collapsing to 0V. This makes the signal unreadable by the receiving circuit. The design works great at temps above 0C, but I am having lots of issues below 0C!

over 6 years ago

0 Kent Closson over 6 years ago

Prodigy 30 points

The design is powered at 3.3 volts and all the capacitors are TRS3253E-failure-at-cold.pdf0.1 uF (X5R) as recommended via the datasheet.

0 Hao L over 6 years ago in reply to Kent Closson

TI__Mastermind 25705 points

Kent,
Sorry to hear your problem. Can you check the voltage rating of the capacitors? We recommend using 10V or 16V caps. Can you also check the resistors (R2503, R2505) spec to be sure the device is not in auto shunt down mode at low temp? Usually if the device doesn't work well, the first indicator is the voltage of V+/V- pins. Thanks,
Hao

0 Kent Closson over 6 years ago in reply to Hao L

Prodigy 30 points

I have identified the issue. The cable I was using had a short on the DSR signal that when removed everything works fine.

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TRS3253E: Issue with RS-232 output drive at cold temperatures below -20C