PMOS as pullup & NMOS as pull down. why?
PMOS as pullup & NMOS as pull down. why?
why PMOS is used as pullup device and NMOS is used as pull down device?
Re: PMOS as pullup & NMOS as pull down. why?
NMOS can pull-down output to 0V but it can pull-up maximum to VDD-Vtn. So it is bad-1 and good-0. PMOS can pull-up output to VDD but it can pull-down to Vtp. So it is bad-0 but good-1 where Vtn,Vtp are threshold voltage for NMOS and PMOS respectively. Also check below link.
viewtopic.php?f=11&t=6
viewtopic.php?f=11&t=6