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mosfet driver question
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mribble:
I want to drive a large mosfet with microsecond pulses.  I want to use 12V to drive the mosfet.

I used this mosfet driver and everything worked as expected: https://www.mouser.com/datasheet/2/268/21419c-23818.pdf

However, when I used this mosfet driver the output was only 5V when I expected it to be 12V.  https://www.mouser.com/datasheet/2/115/ZXGD3009DY-611094.pdf

I'm using a 5V micro to drive the mosfet driver, but in both cases I'm powering the mosfet driver with 12V.  I seem to be missing something on the second data sheet that tells me about this limitation.  Could somewhat tell me what in the datasheet tells me I can't drive the output at 12V when using a 5V input?
mribble:
Thanks for the reply.  I understood the implementation was very different, but could you explain why the second which you described as BJT connected as emitter follower doesn't work with 12V when the input is 5V?

If I look at the internal schematic in the data sheet I'm just switching 2 transistors which would seem to work.  But I'm sure I'm overlooking something so I'm asking for a bit more of an explanation on why my assumption is wrong.
james_s:
Because that's what an emitter follower does. It is effectively a unity gain buffer, the output voltage will follow (be the same as) the input voltage. If you put 5V on the input, you will get 5V on the output, which is precisely what you're doing.
mribble:
Thanks James!  I was just thinking about it more and came the the same realization by thinking through what happens at the transistor level.
mribble:
Could you experts confirm that this chip would function for my needs?  https://www.mouser.com/datasheet/2/115/ZXGD3002E6-74529.pdf

It looks like it would allow me to drive the big mosfet with 12V even though the signal from my micro is at 5V, right?

It is nice because it is pin compatible.  The footprint is slightly larger, but should solder onto my existing pcbs easy enough.
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