Max load current support by S12/ Magni V

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Max load current support by S12/ Magni V

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sreekanthreddyc
Contributor I


Hi,

 

I am new to S12/ Magni V MCU. What is the max output load current supports on 5V generated by S12/ Magni V MCU.

My on board load current for Pull-up and other logic gates is around 1A with a FOS of 2.

Will these series products support.

 

Thanks and Regards

Sreekanth

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RadekS
NXP Employee
NXP Employee

Hi Sreekanth,

I am afraid that 1A load current is definitely too much for internal power regulator.

For example at S12ZVC: The maximum Load Current VDDX1 (without external PNP) is 70mA for VSUP>6V and junction temperature in the range -40°C < TJ < 150°C.

In the case of higher load current, you may use external PNP transistor for carry generated heat out.

But even for the external transistor, it might be a tough task.

When VSUP = 12V and VDDX =5V and IDDX = 1A, then PNP transistor must radiate/convey 7W and this really needs some good heatsink. In that case, you cannot keep external PNP close to MCU and long connections could present additional problems with voltage drops, inductances, ….

It seems that you have plenty of pull-ups and logic gates on your board. Shouldn’t be reasonable to increase pull-ups and replace these gates by any other technology with lower power consumption – if possible?

Personally, I will definitely start thinking about switching power supply instead LDO solution – if possible. This could eliminate a problem with radiated heat, but it increases requirements on filtering, EMC,…

Anyway, if you choose external 5V power regulator and connect it directly to VDDX, you should connect also VSUP pin at the same level for avoiding potential transient effects.

I hope it helps you.

Have a great day,
Radek

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