LPC54606 can not start-up when Fast power on and off

[Weiko]

LPC54606 can not start-up when Fast power on and off，for example,shut off the power supply,  when the 3.3V  down to 2V，and then turn on the power supply,the MCU can not running.But if when the power supply is completely powered off and then powered on,the MCU can running normally.

Is it caused by the configuration of the software?

[Pavel_Hernandez]

Hello, my name is Pavel, and I will be spotting your case, I need more information about this behavior, I found these details on the datasheet, could you tell me how the power supply is doing the peak voltage, do you have an oscilloscope to analyze the measure to confirm if this is out of the spec. 

13. Application information

Best regards,
Pavel

[Weiko]

Thank you for your replay.

Do I have to do is measure the "ta us"?  I found it is <= 20us.  And My conditon is when MCU power down to 2.5V and then ramp up, it also can not start up.

I measure the time from 2.5V to 3.3V,it is 160us.

By the way ,my operation is turn off the power switch and the turn on.If the power fell below 1V,MCU can start up.

[Pavel_Hernandez]

Hello, 

Do I have to do is measure the "ta us"?  I found it is <= 20us.  And My conditon is when MCU power down to 2.5V and then ramp up, it also can not start up.
Not really, we need to analyze where the power-on starts until the behavior you describe.

I measured the time from 2.5V to 3.3V,it is 160us.
Could you share the image of your measure? please. 

By the way ,my operation is turn off the power switch and the turn on.If the power fell below 1V,MCU can start up.
Well, if the power falls below 1V is under spec, and need to follow the start-up again.

Best regards,
Pavel

[Weiko]

Thank you.

Now I found new condition.When the MCU work,I pull down the RST and then release,the MCU also can not work.So I think it may be not the influence of power on and off.

I measure the boot pin.it has 10K resistor pull up to 3.3V,and I measure the waveform,it is High when reset.

[Pavel_Hernandez]

Hello, I will create a new case internal to continue the support in that line.

Best regards,
Pavel