Which gate is normally preferred while implementing circuits
using CMOS logic, NAND or NOR? Why?

Answer Posted / balaji kalluri

if u look at the structure of cmos-nand gate,u cud find the
parallel pmos pull-up transistor configuration whereas in
cmos-nor gate its series config,so the effective resistance
offered by 2-pmos transistors even when they r conducting
due to small Rds (drain-to-source resistance)are smaller in
comparison to the same offered by series pmos in nor
gate..hence the current delivered to the output during HIGH
o/p condition is more for nand gate,due to which it has the
ability to drive more no. of loads of similar type ,thus
offer improved FAN-OUT than cmos-nor gate.
I feel tat this could be the reason..it is true fact as per
WAKERLY text book..but there cud be 'n' no of other reasons
too..think over

thankx..
balaji kalluri

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