How to get a large resistor in cmos process?

[sk1105]

linear mos resistor

i want to realize a mos resistor biased in weak inversion to get a large resistance.(>1meg) but it's a little hard to bias, and hard to get a more linear resistor.
anyone who have done this give some suggestions please.
Thank you!

 

[dingjingfeng]

mission imposible!!!
maybe you can try a off-transistor !!

 

[VSMVDD]

use a fetlington instead like a vn66

 

[pfd001]

It is easy for you to get a large resistor if you don't want accurate resistance. A mos transitor with a large channel length working in the linear region can meet your requirement. Sometime the channel length can be make larger than 100um

 

[shaq]

Switched-Capacitance does.

 

[adsl]

HR poly is pretty good in 0.18um.

 

[butterfish]

1meg ohm is not large, use a pmos in linear region.

 

[adsl]

mos resistors suffer from process and voltage variations.

 

[jerryzhao]

YOU should better tell us the applaction for your resistor. The large lenght MOS for resistor I usually use it in POR circuits