What is the max. allowed values of R, L, and C on chip??

[knack]

Hi,

In design of a complete PLL on chip using 130nm technology, what's the maximum/minum allowed values of on-chip resistors, capacitors, and inductors (R,C, and L)..

Also, is there some tricky ways to override these values (e.g. MOS resistor and capacitor rather than poly R and MIM cap. ...etc.)

Thank you
--Knack

 

[Btrend]

Also, is there some tricky ways to override these values (e.g. MOS resistor and capacitor rather than poly R and MIM cap. ...etc.)

MOS cap can be used in the LPF section, and resistors should use poly type (cause it has lower value of Voltage coefficient (VC)) and usually the resistor area is small as compared to MOS cap., so there is no need to replace it with MOS resistor.

 

[hung_wai_ming@hotmail.com]

Max. RLC depends on the loop equations to provide enough phase margin. Other than that, all other parameters are minimal importance.
You can of coz choose to select MOS resistor and capacitor, however, just the variation would be quite large and you need to leave margin for design only.

 

[knack]

FThank you all,
But it seems that you still didn't get what i want to know..
From your replies, if i don't know, i may go to use a 1µF on Chip cap and 1MΩ resistor!!!!!!!!!!
I want numeric typical values

Thanks
Cheers,
-- Knack

 

[hemlock]

First off I assume you mean low frequencies or @ DC. Things can change drastically at high frequencies.

Secondly you should go to your 130nm Design Manual and look up what types of passives are allowed for your process. (MiM, VNcaps, NFETcaps; just to name a few types of capacitors). The design manual will give you equations for how to calculate the value of your passive element as a function of area.

Next figure out how much area you can waste on passive elements. If you want to take make your whole chip into a giant inductor go for it. Ask Intel to make you a 45nm, 12 inch wafer cap!!

Thus we can't tell you what the max sizes are, its all about trades offs.

Here are some rules of thumb:
1nF is really large for caps
10kohms or less for resistors
10nH for inductors

Next thing to consider is that just about any passive can be faked (crappy faked) with transistor. Long channel length transistors for Mega-ohms resistors, inductor being replaced with transistors in tank oscillators, and lots more tricks.

Cheers,
Hemlock

 

[ahmad_abdulghany]

Depends on the technology, size of chip.. But generally values should be small...