On 24/05/2011 05:20, V G wrote:
> Could you please suggest an alternative N channel MOSFET suitable for thi=
s
> use? The gate is being switched at 3.3V.

loads
VN2222LM is only one.
260mA @ 25C
160mA @100C
you need 100mA. There are T092ish parts (with SM alternatives) that do 200m=
A
Note that VGS in data sheets may be to allow MAXIMUM current, or MINIMUM=20
resistance at Max Temp, rather than "good enough"

ie. might be 8 Ohms at 3V drive, 2 Ohms at 10V drive, but  8 Ohms is=20
80mW at 100mA, and not enough to be a problem for relay. Since input=20
impedance is high there may be more than 3V drive.

There are loads of parts that may be suitable BS170 is lower power but=20
may only dissipate 20mW @ 500mA
Check out 2N7002 etc About 4 Ohms @ 3V drive. SOT and T092, 200mA

The BS170 looks a little better.

BS170 & 2N700x Very cheap.


--=20
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