Hi,

I intend to use a nwell resistor in my circuit. In my symbol library, I see three pins for a such a resistor and I am not clear about the function of the third pin. Is this (probably) some nwell connection ?? Do I need to connect this "extra" terminal to 5V or 0V ?? (This is no PMOS implemented in nwell)

I viewed the layout and I can figure out only two connections there (The nwell resistance is in nwell and there are two n+ contacts for the two terminals).

The third terminal is for P-Bulk connection. The NWell-resistor model takes in to account NWell-P-Bulk diode and parasitic capacitances to the P-Bulk as well.

I think you should have a very good reason to use NWell-resistor in your design (temperature sensor???). This resistor is very bad. It has very bad matching properties. It has very high parasitic capacitance. The sheet resistance variates +/- 40% with the process, it also variates 100% with temperature (0C-100C), it depends also on N-Well - P-Bulk voltage (non-linear), the profile of conductive layer is changing with the voltage across the length and it gives a good chance to get into the latch up (if 1 terminal of this resistor is connected to VSS).

I suggest to use non-salisided POLY resistor instead.