lavitaebelle said:Usually MOS transistors in triode region are used for switches. Depending on the configuration, either an NMOS or a PMOS or a combination of both is used.
The length of the MOS is kept minimum to reduce parasitic capacitances. Depending on the application, the Width is adjusted.
Important things to be kept in mind is that the switch has finite on resistance, and this resistance varies in the DAC chain as all switches dont see the same drain and source voltages. This may cause DNL errors.
Also the leakage current has to be kept in mind.
Syukri said:better use transmission gate rathe rather than nMOS switch....no Threshold voltgae drop