LPC1778FBD144 communication abnormality

[zhaoninggu]

Hello, the LPC1778FBD144 is used in our company's communication module products. Recently, during the 60-degree aging test, we discovered that some of the communication modules exhibited the following issues: when the temperature exceeded 60 degrees, the indicator light of the communication module chip would stop blinking, resulting in abnormal communication. However, when the temperature cooled down to around 50 degrees, everything returned to normal. Upon replacing the LPC1778FBD144 chip, the module communication resumed normal operation. Interestingly, when the problematic chip was removed and soldered onto a normal module for testing, similar abnormalities were observed. What are the common causes of such occurrences?

[merry678]

Hello,
I hope u found some info in my answer.
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Best Regards
merry867

[merry678]

Hello,

Temperature Sensitivity of Components: As you mentioned, certain microcontrollers or internal components might behave unpredictably when exposed to high temperatures. The electrical properties of semiconductors can change as temperature increases, which could lead to performance degradation or malfunction.

Power Supply Issues: High temperatures can affect the stability of the power supply. If the power regulator or power management system isn't designed to handle the thermal load, it might cause voltage fluctuations, leading to instability in the operation of the microcontroller.

Solder Joint Reliability: As temperature increases, the physical properties of solder joints can change. This can lead to cracked or weakened connections, which may intermittently disconnect the microcontroller from the rest of the circuit, especially under thermal stress.

Heat Dissipation: Insufficient heat dissipation in the packaging of the chip could lead to elevated internal temperatures. This can cause the device to throttle its performance, malfunction, or even permanently fail if not addressed.

Potential Solutions:
Switching the Clock: As you suggested, using a different external clock might help. Choose a clock that is designed for high-temperature environments or one with better stability under thermal fluctuations.

Improved Cooling: Make sure the device has adequate heat sinking or cooling solutions. Even adding passive cooling methods like heat sinks or improving airflow can help manage temperature issues.

Power Supply Review: Ensure that the power supply is rated for the temperature conditions the device will experience. Consider using a more robust power regulator designed for extreme conditions.

Check for Solder Joint Integrity: If possible, inspect the solder joints, especially if the device has experienced thermal stress over time. Reflowing the solder or replacing faulty joints could resolve connection issues.

Better Packaging: If heat is a known issue, exploring chips with improved thermal management or packaging that facilitates heat dissipation might be worth considering.
Best Regards
merry678

[Harry_Zhang]

Hi @zhaoninggu 

Based on the phenomenon you mentioned, it is indeed very likely that it is a problem with the clock, as the crystal oscillator is affected by temperature.

So I suggest you try a different external clock.

This problem may also be caused by the following reasons:,

Temperature sensitive characteristics: Microcontrollers or certain internal components may be more sensitive to temperature. When the temperature exceeds a certain threshold, it may cause changes in the internal circuit characteristics of the chip, affecting its normal operation.
Power supply issue: High temperatures may cause unstable power supply or a decrease in the performance of power management circuits, thereby affecting the power supply of the chip.
Solder joint issue: In high-temperature environments, the reliability of solder joints may be reduced, leading to problems with the connection between the chip and the circuit board.
Packaging heat dissipation issue: The packaging of the chip may not be sufficient to effectively dissipate heat at high temperatures, resulting in high internal temperatures that affect its normal operation.

I hope it can help you.

BR

Hang