Looking for the right transistor.

[BrokenTrace]

Im making a PCB with only smd components. I want to turn on/off a complex circuit of the board with a phisical switch. This circuit needs 600mA, but lets say 1A to be sure, and it is conected to a 16v.



I would like to use the less components possible, but I cannot use only a switch slider to do that, because small ones cannot carry 1A. I will use probably this one, or one similar (1p2t horizontal switch):

http://www.ebay.com/itm/10-Pcs-x-On-On-2-Position-1P2T-SPDT-Miniature-Horizontal-Slide-Switch-SMD-7-Pin-/310569921527

So I have to use a transistor, like this:



I belive that is ok. But, what smd transistor could I use? Can you help me to choose one?

The first problem is that the transistor base is going to be 16v, too much? I cannot regulate that voltage.
Second, the transistor should handle 1A (size problem?)
Third, what could be the value for that resistor? I dont care, I can put any value. The switch can use up to 0.3A, but maybe 20mA is ok for the gate, or what it the perfect value for that? (I cannot see that on datasheets :/)

Im looking for tons of datasheets, but I cannot pick the right one, Im very newbie and also I dont want to ruine the pdb just for this. So could you help me?

Thanks!!

[Paul Price]

What you need is a P-Chan power MOSFET to do the switching job.

ADVANCED POWER ELECTRONICS CORP-AP4435GH-HF-3TR-MOSFET, PCH, -30V, 20MOHM, TO-252

You can get the MOSFET above from Farnell/Element 14/Newark etc.

[sleemanj]

I would use either a P-channel on the high (positive) side, or an N-channel on the low (negative) side of the load.

P Channel: AP2305AGN/AP2305GN  will handle 3A and 20v across it.
N Channel: SI2302DS will handle 2A and 20v across it.

If you want to use a transistor, PNP - SS8550LT1, NPN - SS0850LT1.  Either can handle about 1500mA max with 200-300mW dissipation.

Whichever way you go, remember to pull the gate/base high or low when OFF as appropriate, don't leave it floating.