Hi all,

I have an injector driver circuit board here that's based on an LM1949. =20
It seems to be pretty much the same as the reference circuit in the=20
datasheet (fig 1 here... http://www.ti.com/lit/ds/symlink/lm1949.pdf ),=20
and it's using a TIP122 for the darlington.  Problem is that it's=20
getting VERY hot, and doing the math, that is expected.

The later part of the datasheet shows an option to use it as a switching=20
driver, to reduce that power consumption, but calculations show it would=20
still get quite hot.  Most of it is due to the transistor's ~2V Vce. =20
Looking at other transistors, I don't see much better available, so=20
wondering if there is a MOSFET that I can drop in instead of the=20
darlington.  There is a spec for the drive current out of the LM1949,=20
but not sure about the drive voltage, which I'd need to know to drive a=20
MOSFET.

I'm sure I can drive a small (say 2N2222A) transistor, then have that=20
switch a MOSFET, but I'd have components dangling on the board, so a=20
drop in solution would be great.  Any thoughts on this?

Thanks.

--=20
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