FM4 UART 4 High Temperature

[dchew]

I'm encountering an issue when operating UART 4 at elevated temperatures. The part I am using is S6E2HG6G0AGV20000 which is rated to 125 degrees C. UART 4 on this chip is on pins 5 and 6 and hardware flow control is disabled. When the microcontroller temperature gets to about 70 degrees C the UART 4 transmit/receive operation starts to fail. I am also operating UART 0, 1, and 2 at the same time but those UARTs continue to operate as normal at elevated temperatures. 

Has anybody encountered this issue or knows what the possible root cause could be?

[Roy_Liu · Accepted solution]

Hi,

Possibly the operation temperature is too high. 

Do you refer to the "13.2 Recommended Operating Conditions" in the device datasheet for debugging the problem? Note, the 125 degrees C is the maximum Junction temp, which is not directly measurable usually.

Anyway, 70 ℃ (Ambient temp) is at the edge of over temp if the Pd(Power dissipation) is high,  to debug this, you may check if the problem is consistent with UART 4 on the other board if you have, or lower the Pd(shutdown some other functions of the device) to see if UART 4 can work at the same temp.