hi there, is there any good tutorials to learn about mosfets? mosfet are divided into p type mosfet and n type mosfet? what is the differences between p and n type mosfet with the depletion type and enhancement type mosfet?
To answer your question,
n type mosfet, which is usually called nmos,
lies on a P type substrate. When its turned on,
the conducting channel if formed by an inversion layer of electrons, which connects 2 n-type places.
p type mosfet, is called pmos. It lies on N type substrate. When its turned on, the conducting channel is formed by "holes". and it connects 2 p-type places.
Pmos as name indicates uses holes as carries for operation and we need to apply -ve voltage so that holes will attract and form a layer for conduction..so its Vt is -ve..........for NMOS we will apply +ve volt and carriers are electrons...
Not always... In diff-amp circuits, if there is no headroom wrt the available VDD, most of the time it'll be pmos which'll used as input transistors. You can add to it the current mirror circuitry... there you are, more pmos than nmos...
Of course, I agree with you in that pmos devices are inherently slower than the nmos counterparts..