what is transmission gate

Q1)im a newby,i want to know more about transmission gate that been use as a sampling switch.how exactly it works and about the injection square wave pluse.

Q2)if i doing a sample and hold and using rail to rail op amp. to perform an ADC.is there any characteriistic i need to know so that my opamp will work with sample and hold to perform ADC.
is there any range of gain,phase margin or settling time that need to be satisfy 1st to perform the sample and hold operation.

it is device made by pmos and nmos transistor connected in parallel.
which act as switch. called transmisstion gate.

The transmission gate has one n-MOST and one p-MOST connected in parallel, as said in previous post. The two gates are controled by complementary clock pulse. It is more advantageus from a n-MOST switch because it can operate from -Vss to Vdd with no off-regions. If you want to learn how, try to apply the known MOST equations for strong inversion in both transistors and check their behavior.
The transmision gate certifies that the switch will operate in full scale and that you will have a very low impendance during operation in common scale.

Try to find explanation in Sendra - Smith. They present it quite simple.

I hope I helped,
D.

Added after 2 minutes:

maori said:

Q2)if i doing a sample and hold and using rail to rail op amp. to perform an ADC.is there any characteriistic i need to know so that my opamp will work with sample and hold to perform ADC.
is there any range of gain,phase margin or settling time that need to be satisfy 1st to perform the sample and hold operation.

Click to expand...

Define S/H operation. Are you creating a Switched Capacitor ADC? What kind? There are a hell lot of details you have to be carefull. Please be more specific on this one, I may help you a bit.
D.