lm2676 on/off

Morteza Heydari Araghi

Other Parts Discussed in Thread: LM2676

If the on/off pin of lm2676 is pulled down to ground by a 10k resistor, and then it is directly connected to a 3.3v microcontroller that would turn on the regulator by driving it high, would that possibly damage the microcontroller?

Would you recommend an isolator or it would not be needed at all?

over 9 years ago

0 YangZhang over 9 years ago

TI__Genius 11085 points

When the pin is pulled high by the microcontroller, the current consumed by the pull down resistor is 3.3V/10k = 330uA. It is a very small current I don't think it will damage a logic output. Please check the current capability of the microcontroller output to be sure. -Yang

0 Morteza Heydari Araghi over 9 years ago in reply to YangZhang

Prodigy 120 points

In the details of the chip, looks like the on/off pin would possibly source some small current, which would in turn cause a current sink on the digital pin of the MCU. I would like to know more about the current sourcing possibility of the chip (It is drawn as a current source, connected to a 7 volt zener)

0 YangZhang over 9 years ago in reply to Morteza Heydari Araghi

TI__Genius 11085 points

The small internal current source is only to pull up the EN pin when the pin is open circuit. It will not pull up any output pin of an MCU. It is 45uA max current.

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lm2676 on/off