Which gate has more delay: NAND or NOR?

[spauls]

For W/L ratio of 5/2 which gate has more delay NAND or NOR.

 

[coolrak]

Re: Nand or NOR Delay

I guess NOR has more delay, since the logic effort of NOR is more comapred to NAND.Correct me if i am wrong

 

[ee_expert2000]

Re: Nand or NOR Delay

NAND can be done by having transistors in series.
so the overall resistance will be greater compared to NOR with parallel transistors.
the delay is directly proportional to R.
the NAND will have more delay.

 

[visualart]

Nand or NOR Delay

Which logic do you mean?
Digital logic? or Flash structure?
On the logic, I think the Nor is faster than NAND,
for its P transistor is parallel

 

[acidwabbit]

Re: Nand or NOR Delay

Nor will have more delay for pull up and Nand more for pull down...charging will take more time...Nor will have more delay

 

[sabu]

Nand or NOR Delay

for transmitting a 1 NAND GATE takes more time.for tra 0 NOR gate taks more time( as per cmos design, transmitting 1 means 0/p is HIGH.

check it out
regards

 

[mystique_unbound]

Re: Nand or NOR Delay

NOR gate only .This can be viewed from the circuit itself . You have a series connection of two PMOS of greater W/L (4 times that of nmos to have same rise and fall time ) . so this will increase the charging time in case ogf NOR gate compared to NAND gate .

 

[Resistance]

Re: Nand or NOR Delay

hi,

Think u have got many replys but i think its simple and all boils down to one concept called Rd ON of PMOS and NMOS.. thats all

PMOS has longer Rd ON than PMOS thus it takes more time to switch.

As NOR has PMOS in series and NMOS in parallel it takes more time to switch .. Thats all dude..

REgards.

 

[apradeep]

Re: Nand or NOR Delay

Yes Nor has more delay since it has p-transistors in series
In case of NMOS Nor is faster than NAND
Thanks
pradeep

 

[weng]

Re: Nand or NOR Delay

Hi,

When you say the NMOS and PMOS, you are refering to the peripheral circuits around the flash core array (eg sense amplifiers) but not the flash core array itself.

Am I right?