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# How much does LAMBDA equal in 0.18um process?

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#### holddreams

##### Full Member level 6
early voltage mos 0.18um resistance

How much does LAMBDA equal in 0.18um cmos process?

How much does UnCox equal in 0.18um cmos process?

The mos model files doesn't give these parameters directly,

So I ask here for future circuit design .

I have ever run a simple circuit to calculate these parameters,but not sure.

Thanks.

#### nxing

uncox cmos

find the parameters of BSIM and then the model file from your foundry, you can find (or calculate) these values. For Cox, find tox and then calculate it. you can also find the electronic mobility from any textbook (pay attention to its variability with short -channel device)

m.Rostami

### m.Rostami

Points: 2

#### holddreams

##### Full Member level 6
0.18 um uncox

Then how much LAMBDA and UnCox do you use when you first calculate your circuits W/L?

#### starcoming

##### Member level 1
determining uncox of transistor

different technologies have different model parameters.

#### cretu

##### Full Member level 2
lambda 0.18 um

if I remember from "the old days" and from what the guys at Berkley are saying
you can define lambda in 2 ways

1.Lambda as a measure of device output resistance, where ro = (lambda*IDS)-1 . The units here are 1/volts
2. Lambda as a design rule parameter. Lamda specifies the minimum dimensions of
your devices. The minimum gate length is typically 2*lambda

You are interested in the 2 one I guess
so for 0.18um, lambda=0.09um

Regards

PPS Sutapanaki is irght..that was a rule of thumb usually above 0.5um

mhjedaboard

### mhjedaboard

Points: 2

#### sutapanaki

what does cmos 2 * lambda = l

Unfortunately, for the sub-micron technologies, there is no easy design formulas where you can use the quadratic equations. You can still use them to approximate the answers (very approximate), but in this case you also don't need accurate values for lambda and uCox. So, I guess, any value that you can extract from simulations will be OK, but will not be accurate.
ro of the transistors is changing with Vds for constant Vgs anyway, so lambda has little meaning nowadays. Plus if you try to extrapolate the Id(Vds) curves of a transistor, they don't intersect at one point on the x-axis (Early voltage).
For good design practice try to search matterials about gm/Id based design approach.

mhjedaboard

### mhjedaboard

Points: 2

#### holddreams

##### Full Member level 6
cmos 0.18um cox

Here I have a question:

If I know the LAMBDA and UnCox ,I can calculate the W/L of each mos transistor approximately .And then ,according to the simulation result ,some of the mos transistors should be modified the W/L until the circuit meet the spec.

When you design a circuit,how will you first give the W/L?By hand calculation?or else?

Thanks.

mahmoud esmail

### mahmoud esmail

Points: 2

#### playdc2002

##### Junior Member level 3
define lambda for cmos device

use simple nmos or pmos
sweep the vds and w/L, get a bouch of vds vs Id curve, then you will have a rough idea about how much is the lambda

#### goodboy_pl

##### Full Member level 5
0.18um cox

lamda is a historic mathematical design value but cox is physical.
infact u can find cox in .model of available transistors, but there is no lamda in models.

lamda was used for old scalable processes like over 1 um not suitable for sub micron and ultra deep sub micron technologies.

it was only a mathematical value to simplify design entry in sch and layout editors.
design rules was based on lamda but recent technologies have very complicated and independent design rules which makes lamda useless!

BEST!

#### Syukri

##### Full Member level 5
0.18um nmos cox value

In 0.18µ ...λ=0.1µm or = 100nm.

Sorry I've forgot the value of the capacitance...let me chack out, and if it's still unanswered in my next login i'll tell ya

bye

#### cliffj

##### Member level 3
how much is 1 lambda

lamda is for spice model level 3 or 1. And now the mos model for hspice
is spice level 53. There is no such value you can find in the sub-micro process.

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