Transmission gate question ?

[master_picengineer]

Hi jankin,
Please can you elaborate or have you a tutorial Material explaining that.
Thanks

 

[hr_rezaee]

Thanks,
but I still don't understand the difference between Vss and Vdd.
Any devices.

Hi
ohhh, No
PMOS bulk is connected to source in that schematic.
but P-N junction of bulk-drain cab be forward bias in this situation.
so, for correct operation of switch in this example bulk of NMOS must be connected to Vdd.

for NMOS it depends technology that you are using. if you have twin-well there is no problem to connect NMOS bulk to anywhere but if you have just N-well you mist connect all NMOS Bulks to the lowest voltage in your circuit.
regards

 

[master_picengineer]

Thanks hr_rezaee,
I understood that NMOS Bulk is connected to the ground and PMOS Bulk to the source. I'm confused because I have 3 components in my analog design envirement library which are the following:

Did you understood What I meant ?
Thanks

 

[Ghitani]

Choose supply levels same as input voltage levels

 

[hr_rezaee]

Hi
it is just a name.
you must connect it to highest voltage that can be across PMOSs.
if this voltage is Vss, you must connect it to Vss.
but Vss is usually below zero potential.
regards

 

[master_picengineer]

Hi,
Ok now I will use onlu Vdd in all my design as a source.
Thanks you All.

Added after 16 seconds:

Hi,
Ok now I will use only Vdd in all my design as a source.
Thanks you All.

 

[dinesh agarwal]

bulk of pmos to the highest supply that is VDD and the nmos to the lowest that is GND