THank you for the suggestions.
The switch is to be used in a current scaling DAC. PMOS devices are being used as the current sources, based on the current and overdrive requirements i have chosen the length of these transistors to be 4um(min length allowed is .35um).
1. To maintain matching, if i use the same length(4um) for the switches then turning the swtiches on/off will take more time because of the relatively large capacitances.
2. To have a better switching speed, if i choose the length of the switches to be the min length ie. .35um the lengths of the currnet source transistors and the switches are not the same, non uniformity of lenght of devices, and this can lead to unexpected behaviour of the circuit. Is it not?
So, what should i choose for the lenght. Please help me out.
Thank you!!