Hi,
I think there is a conflicting info about EN pin of MP8715 in its datasheet.
Firstly in the absolute max ratings it says :
However in the pin descriptions it says :
So if we tie EN pin to VIN with 100K as datasheet says, and we apply 20V to the input, we will see around 18V on the EN pin which is much above the maximum ratings…
Less of a conflict than you suppose. They probably should develop some verbiage and put it in every data sheet.
The abs max is for a voltage from a zero output impedance source. Like for instance a power supply
The pull to Vin with a 100k resistor is definitely not a zero ohm output impedance source.
What happens in that case it the ESD protection device internal to the chip, (think zener) clamps the voltage at the pin probably to 7 or 8 volts by sinkin 20uA of current and dissipating 160 uW of power. Try it and see
For another similar chip, MP2338, it says :
I think this voltage divider warning might be forgotten in the datasheet of MP8715 …
Me I bet on the 2338 you could pull the pin high through a 100k to the rail no problem. MPS doesn’t always do the best data sheets. Any I know for a fact that many chips have EN pins which work fine as long as there is a current limit. MPS could resolve the confusion if for instance they specified an abs max current into the pin.
Yes I think it is better to say absolute maximum rating is equal to the input voltage, because if they say 6.5V maximum in datasheet, normally we should implement a voltage divider to not exceed the max voltage.
Resistors cost 1/1000 of a cent these days? Aren’t you stuck with a 5 to 20V input range? So there isn’t really a divider that can do that 1.6V at 5V and less than 6.5V at 20, is just possible.
