MC56F8367MPYE, Date code: XAA1315

[a8Chcx]

Hi,

I am using "MC56F8367MPYE" to control the DC motor and works fine for long time.

Then, we produced the new batch of product and have the following problem:

1) When I power on the chip, it causes MOSFET shortage. I checked the reason and found that some pins of PWMA and PWMB are high after power-on. Based on the datasheet, all PWM channels are disabled after POWER ON or RESET.

2) Date code: XAA1315. Can you tell what it means?

We need to know what the exact problem is and how to fix it?

Thanks,

Christie

[xiangjun_rong]

Hi,

I think it is common practice to connect 10K ohm pull-down external resistor for each PWM pin, during/after Reset, all the PWM pins are in input mode, the pull-down resistor can pull the pin to LOW, which avoid the damage of the power device because of shortening when you set up the power device in a H bridge.

BTW, I suppose you know that you have to add dead time for the complementary PWM signals.

Hope it can help you

BR

XiangJun Rong

[xiangjun_rong]

Hi,

I think it is common practice to connect 10K ohm pull-down external resistor for each PWM pin, during/after Reset, all the PWM pins are in input mode, the pull-down resistor can pull the pin to LOW, which avoid the damage of the power device because of shortening when you set up the power device in a H bridge.

BTW, I suppose you know that you have to add dead time for the complementary PWM signals.

Hope it can help you

BR

XiangJun Rong

[a8Chcx]

Hi XiangJun,

Thank you for your input. Here are more explanations:

1) It happens on 30% of boards. And these design is used for last several boards and works fine...

2) I have 10K pull-down on all PWM channels.

3) This happens on POWER UP stage, no any software loaded in MCU

4) When I remove MOSFET, no over-current happens.

5) I measured PWM pins, some pins are HIGH. That is the reason causes shortage...

6) I measure the current. When I power ON, it consumes around 130mA, then go up to 160mA, then MOSFET shortage because of HIGH on PWM pins.

I really need your help to see where the problem is and how to fix?

Can I send no function MCU to NXP to confirm?

Thanks,

Christie

[xiangjun_rong]

Hi,

does the issue only occur on the branch with data code XAA1315?

The issue is that the PWM signal are high during the power-up process before any application code is executed, and the external pull-down resistor can not pull the pin to LOW logic, which leads to MOSFET damage during power-up process.

You can contact local FAE or DFAE, have them to contact failure analysis team.

BR

XiangJun Rong

[a8Chcx]

Hi Xiangjun,

It happens on XAA1315 and XAC1493.

It happens during POWER-UP, no any code is loaded to MCU. The pull-down resistor does not pull down PWM signal.

I am located in Canada, where can I find FAE?

Thanks,

Christie

[xiangjun_rong]

Hi,

I have contacted AE team, maybe they know if the batch with date code XAA1315 has issue.

I will send you a reply after I get feedback.

BR

XiangJun Rong