PIC PWM and H-Bridge

crutschow said:

The On-resistance information tells you what gate-source voltage the manufacture uses to characterize the on-resistance. That means you should not normally use less than that if you want the MOSFET to operate as a switch with a low on-resistance.

Both the transistors you listed are characterized at both a Vgs of 4.5V and 10V so you can use either value, depending upon how low you want the on-resistance to be. Thus 6V for your circuit should be fine unless you want the absolute lowest on-resistance.

If you operate the N-MOSFET from a TTL output, which is typically only about 3V, you should add a pull-up resistor (say 1k) from the TTL output to the +5V voltage so that the gate voltage goes to 5V when the transistor is on.

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