How to design and connect some CMOS gates

[mtkee2003]

Hi,

First >> i want to connetct some CMOS gates (like AND, OR , ...) together.
how can i do this?

Second >> i want to design some gates (like AND, OR , ...) with CMOS technology.
help me please.

regards, Mostafa

 

[road_0506]

Re: CMOS Gates

Hello Mostafa,
What do you mean design? Is it ckt or layout designing?
Regards,
Ronald

 

[fede76pc]

Re: CMOS Gates

Hi Mostafa,

well, in order to connect different gates, the first thing you to check are the nise margins. In particular, each logic gate is characterized byfour different logic level: V_IL, V_IH, V_OH and V_OL.
V_IL is the maximum input voltage identified as a '0'.
V_IH is the minimum input voltage identified as a '1'.
V_OL is the maximum output voltage related to a logical '0'.
V_OH is the minimum input voltage related to a '1'.

If you want to connect gates that have to properly exchange information is mandatory, and also obvious, that the output voltage levels of the driver have to be recognized by the receiver as valid input voltage.
In particular, you have to verify that:

V_OH > V_IH
V_IL > V_OL

When you use gates of the same family, these relations are always verified, but when you have to adopt different logic families (eg 74LS with 74HC) you have to verify the above relations.

Howeverfrom your post seems that you are planing to adopt gates from the same family, so htere will be no problem. You only have to check the currect FAN-OUT, i.e. the maximum number of gates a single port can drive.
Each gate is characterized by 4 different current levels: I_OL, I_OH, I_IL, I_IH.
You have to retrive: | I_OH/I_IOH | and | I_IH/I_IL | and take the minimum. This will give you the FAN_OUT.

If you want to design your own CMOS gate, well, the first thing to do is to properly design the transitor's features (length and width). Usually nmos are designed using minimum feature transistors, while pmos dimensions are retrived imposing the equivalence between β_p and β_n of the equivalent inverter.
However you should better take a look at some good books like classical "Weste, Eshraghian" or "Rabaey, Chandrakasan,Nikolic´" for better understand how to design a CMOS gate, how to retrive its equivalent inverter and from it how to derive the transistor's features.

Enjoy it,
Fede

 

[ahmad_abdulghany]

Re: CMOS Gates

Hi,

First >> i want to connetct some CMOS gates (like AND, OR , ...) together.
how can i do this?

Second >> i want to design some gates (like AND, OR , ...) with CMOS technology.
help me please.

regards, Mostafa

Read more about that in 'Digital Integrated Circuits' by Rabaey

 

[mtkee2003]

CMOS Gates

hi ahmad_abdulghany
thanks

where can i download this book?

regards, Mostafa

 

[ahmad_abdulghany]

Re: CMOS Gates

hi ahmad_abdulghany
thanks

where can i download this book?

regards, Mostafa

I don't know if the book is available in electronic format,
i have the original book,
but you may search for it in eMule or here on the board,

Sorry,
Regards,
Ahmad,

 

[salma ali bakr]

Re: CMOS Gates

i guess you may have already found the book mostafa but here is the link anyways

 

[ltrainna7]

Re: CMOS Gates

just be careful of static charge

 

[ashiremah]

Re: CMOS Gates

In CMOS design we have cosider in Complementory system....for eg Invertor it consist of one nmos and pmos in series and start with basic like NAND and NOR.... in case of NAND gate first connect two nmos in series and connect pmos in parallel then connect these two in series the pmos at the top side (VDD) and nmos at down side (VSS)..same for NOR gate revers the connection of AND gate....

 

[mohammed.peer]

Re: CMOS Gates

i guess you may have already found the book mostafa but here is the link anyways

h**p://

At thins link information shown was like this
"The topic or post you requested does not exist (it was removed)"

 

[salma ali bakr]

Re: CMOS Gates

when i made my reply i had it working fine and i downloaded the book even
dunno what has happened at allllllllll !!!

 

[narfnarf]

Re: CMOS Gates

i think you have to be a certain member level to see certain post (i am not sure...?)
i can see that post just fine...

maybe edaboard acting weird try again later mohammed.peer

 

[nguyennam]

Re: CMOS Gates

Hi,

First >> i want to connetct some CMOS gates (like AND, OR , ...) together.
how can i do this?

Second >> i want to design some gates (like AND, OR , ...) with CMOS technology.
help me please.

regards, Mostafa

2 questions just look like not related to each other.

For the first- yea, you can connect in series (to make a certain digital circuit) as far as you can imagine.

You can connect the outputs of the gates in parallel (for the purpose of getting higher output current), only when the gates are in the same package.

For the second- I can't imagine what you want to design: the CMOS gate itself in semiconductors, or the circuits using CMOS gates, whilst you do not how to connect the CMOS gates together, means no idea about CMOS gates.

nguyennam

 

[manguonmo82]

Re: CMOS Gates

Chào các bạn.

Ai có sơ ðồ của cổng NOR họ CMOS 4 lối vào thì cho mình mới. Mình ðang cần gấp. Rất mong nhận ðược sự giúp ðỡ của mọi người.

Thanks a lot.