micro controller overheat - Page 1
Forum section: electronics / repair

author: Farah
author_rank: Contributor
timestamp: August 26, 2023, 03:48:46 am
content: I have a TMS 320 series microcontroller on the instrument, when the temperature of the instrument exceeds 75 degrees Celsius, the output data of the micro is not correct, how can I reduce the temperature of the micro? Is it correct to use a heatsink? I have limited space in my tools.

author: Kim Christensen
author_rank: Super Contributor
timestamp: August 26, 2023, 04:30:14 am
content: No heatsink is going to cool a device below ambient, so if the heat is not being generated by the microcontroller, putting a heatsink on it would be useless.Maybe a fan that draws cooler air from outside the instrument could work. (sucks air in the front and blows it out the back)

author: DavidAlfa
author_rank: Super Contributor
timestamp: August 26, 2023, 05:00:56 am
content: 75°C? It's not normal for most MCUs to get so hot, maybe it's damaged?

author: srb1954
author_rank: Super Contributor
timestamp: August 26, 2023, 06:16:57 am
content: Quote from: Farah on August 26, 2023, 03:48:46 amIf the ambient temperature is 75℃ then it already exceeds the maximum operating temperature of 70℃ for the standard commercial temperature range part. Adding a simple heat sink is not going to be of much benefit and you will have to resort to active cooling measures, possibly a Peltier effect cooler or a heat pipe to an external heat sink in a lower ambient temperature area. Both of these options will take up considerable space in your equipment.If you can't fit these in you may have to resort to the mil-spec temperature range device SMJ320C25, which allows up to 125℃ operating case temperature. Good luck finding one of those at a reasonable price.

author: EggertEnjoyer123
author_rank: Frequent Contributor
timestamp: August 26, 2023, 06:21:17 am
content: Do you have enough ventilation for your system?

author: Farah
author_rank: Contributor
timestamp: August 26, 2023, 08:48:00 am
content: It's a downhole tool and using a fan inside the tool is impossible.

author: Farah
author_rank: Contributor
timestamp: August 26, 2023, 08:50:15 am
content: In datasheet of Micro, Operating free-air temperature ranges is − 40°C to 85°C.

author: Farah
author_rank: Contributor
timestamp: August 26, 2023, 08:53:18 am
content: The limited space inside the tool and the factory design of the tool do not allow any kind of change.

author: Farah
author_rank: Contributor
timestamp: August 26, 2023, 08:57:33 am
content: This is a downhole tool whose electronic circuit is inside a large metal tube. Only the power part of the tool is equipped with a heat sink.

author: voltsandjolts
author_rank: Unknown
timestamp: August 26, 2023, 09:33:20 am
content: Downhole oilfield tools commonly use microcontrollers beyond their temperature rating. Microchip PICs are quite popular for this market, some of them operate well at temperatures to 200C. I have also seen TMS320 series used downhole.Quote from: Farah on August 26, 2023, 03:48:46 amYou could use a peltier cooler to gain a few degC but if you are running on battery power, that's not going to work.The proper solution is to use components which work at high temperature, either rated by the manufacturer, or by you after your own quailification testing.I would be surprised if your TMS320 really is failing at anything below 100degC. Perhaps some analog inputs are going awry and TMS320 is making decisions on bad inputs, that would not be a MCU fault. Also check your clock speed, lowering it can help at higher temperatures.

author: voltsandjolts
author_rank: Unknown
timestamp: August 26, 2023, 09:58:30 am
content: Is this something you are designing, or something you are repairing?

author: Berni
author_rank: Super Contributor
timestamp: August 26, 2023, 10:30:50 am
content: Just use a different MCU.I had STM32 MCUs rated for 105°C running at 160°C just fine. Downclocking can also help

author: Farah
author_rank: Contributor
timestamp: August 27, 2023, 03:44:22 am
content: I'm repairing this tool.

author: Berni
author_rank: Super Contributor
timestamp: August 27, 2023, 05:51:38 am
content: Still the same answer. If the MCU stops working when hot, replace it, since it is not normal for MCUs to just stop working at such a low temperature.Tho also make sure it is not any of the components close to the MCU, since heating up the MCU to test it likely also heats the surrounding components quite a bit too.

author: iMo
author_rank: Super Contributor
timestamp: August 27, 2023, 06:33:18 am
content: Quote from: Farah on August 26, 2023, 03:48:46 am"The temperature of the instrument" - where do you measure the temperature actually??T_instr could be 75C, T_TMS320 could be 78C or 200C..

author: Farah
author_rank: Contributor
timestamp: August 27, 2023, 10:28:03 am
content: On logging surface system (record logging curve and image) that acquis data of instrument shows MCU temperature.

author: langwadt
author_rank: Super Contributor
timestamp: August 27, 2023, 12:18:47 pm
content: are you sure it is the MCU and not other components on the board?

author: Farah
author_rank: Contributor
timestamp: August 28, 2023, 03:30:51 am
content: When I touch the MCU, it's very hot