Model description and parameter extraction

AN2657

6/18

Equation 5

Another important parameter to define is the gain factor with zero bias. Referring to

degradation). Equation 8 and 9, which define the drain saturation voltage, complete the set

of equations needed to define the generator current (Equation 10 and 11).

Equation 6

Equation 7

Equation 8

Equation 9

Equation 10

Equation 11

The automatic ADS optimizer was used to extract the parameters for the current generator.

The threshold voltage and the gain factor have been extracted from the input characteristics

with Vds at a low voltage level. Concerning mobility degradation, the transconductance

parameter was used varying Vds and with Vgs at a high voltage level. The sub-threshold

voltage was extracted from the input characteristics with a gate voltage level below the

threshold voltage level.

KP

KP0

T

° K

()

T

()

----------------------------

⎝⎠

⎛⎞

DTKP

⋅

=

-

FV

gst

()

1

1T

V

vgT

gst

T

I

V

I

gst

⋅

I2

=

9

∑

+

⋅

+

⎩

⎪

⎪

⎨

⎪

⎪

⎧

=

V

gst

0

≤

V

gst

0

>

KP

EFF

KP

FV

gst

()

--------------------

=

AL0

2

L

2

–

=

B

L

δ

---

L0

2

⋅

=

CKE

L

3

⋅

=

δ∆∆VG Vgg

⋅

+

=

D

1

BA

–

()

Vgg

V

TH

–

() C1 δ

–

()

⋅

–

⋅

=

D

2

D

2

1

4C

Vgg

V

TH

–

()

1

δ

+

()

0.5

A

B

–

⋅

()

⋅⋅

⋅

⋅

–

=

δ∆∆VG Vgg

⋅

+

=

VDSAT

D

2

D

1

+

1

δ

+

()

2B

A

–

⋅

()

⋅

------------------------------------------------------

=

I

DS

KP

EFF

Vds

V

( gg V

TH

–

0.05

Vds

1

∆

+

() )

⋅

⋅

–

⋅⋅

IDSS

1

A

Vds

VDSAT

–

BVDSAT

C

+

⋅

-------------------------------------------

⋅

+

⎝⎠

⎛⎞

⋅

⎩

⎪

⎨

⎪

⎧

=

V

DS

VDSAT

<

V

DS

VDSAT

≥

IDSS

KP

EFF

VDSAT

Vgg V

TH

–

0.5

VDSAT

1

∆

+

()

⋅⋅

–

()

⋅⋅

=