MSP430F67791A: Microcontroller Reset Issue During Electrical Fast transient test

Prafulla Salunke

Part Number: MSP430F67791A
Other Parts Discussed in Thread: STRIKE

Hello,

I have designed meter using MSP430F67791A for analog voltage and current input measurement. While testing the prototype for EFT(IEC 61000-4-4), micro controller is getting reset on 2kV and further.

I am using Port 6 declared as output. P 6 .7 is declared as active high and P 6.6 is declared as active low. While EFT test is going on, i checked for 3.3V power supply, which is remaining intact. But voltages on P 6.7 and P 6.6 are 23 mV and 2.57V . This voltages are continuously changing. After completion of test prototype resumes its working.

Please help me to solve this.

Regards,

Prafulla

over 8 years ago

0 James Evans over 8 years ago

TI__Mastermind 49692 points

Hello Praful,

Thank you for your post. I see that you're performing the IEC 61000-4-4 test instead of IEC 61000-4-2. Looking at our IEC 61000-4-x Tests for TI’s Protection Devices app note, the IEC 61000-4-2 test is related to system ESD immunity whereas the IEC 61000-4-4 test is related to Electrical Fast Transient Immunity (EFT). Section 2.3 discusses using transient voltage suppression (TVS) diodes to supress the EFT events. Figure 5 illustrates the expected bursts and waveforms.

Since our TI Designs have been targeted towards IEC 61000-4-2, they use varistors as the protection devices. These work fine for an ESD strike, but they tend to age or degrade over time when exposed to bursts over extended periods of time, which could be the reason why you're seeing the device stop. Thus, I would suggest adding TVS diodes to your system in parallel with varistors to protect against EFT events. I'd recommend looking at the following resources as well.