Choice of FET

[Scampy]

Richard, having problems locating them in the UK - Only Farnell stock them, and as I have an account with RS would prefer to get something from them. This is the closest I can find on RS

http://uk.rs-online.com/web/p/mosfet...stors/8648710/

Would this suit my needs ?

[HenrikOlsson]

Looking at the Farichild FDS 8949 it has a specified Rds-on of 36mOhm (max) at a Vgs of 4.5V and 4.5A drain current.
36mOhm at 2A drain current equals a power dissipation of 72mW per switch or a ~150mW for both in the package.

The thermal resistance, when using minimal pads, are specified as 135°C/W so the package temperature will increase by ~20°C, it will feel warm but not hot.

Looks like it should work just fine as long as you keep the Vgs "up there".

/Henrik.

[Scampy]

Many thanks guys.. I'll sort out an order and do some real world tetsing

[MichelJasmin]

FDS6690A
Single N-Channel, Logic-Level, PowerTrench MOSFET

11 A, 30 V
RDS(ON) = 17.0 mW @ VGS = 4.5 V