Model Parameter

Description

Unit

Default

LEVEL

3 is required to select one of several MESFET models (see SAT parameter)

None

1 (default if LEVEL parameter is omitted)

SAT

Saturation factor (MESFET model selector)

0 = Standard Curtice model
1 = Curtice model with tanh coefficient
2 = Statz cubic approximation to Curtice model with gate field degradation

3 = Variable saturation model or Triquint extended (TOM) model

None

0

A

Active layer thickness

Aeff = A ´ SCALM

Meter

0.5e-6

ACM

0 = SPICE method

1 = physical basis (required for Triquint TOM features)

None

0

AF

Flicker noise exponent

None

1.0

ALIGN

Correction for gate misalignment

Meter

0.0

ALPHA (ALFA, ALPHA1)

Saturation factor

Volt^-1

2.0

AREA

Area factor

None

1.0

BETA

Transconductance (gain)

Amp/Volt²

1.0e-4

CAPOP

Capacitor model

0 = SPICE depletion capacitor model
1 = Statz charge-conserving symmetric capacitor model
(Level 3 only)
2 = Modified Statz model

None

0

CAPDS (CDS)

Drain-source capacitance

Farad

0.0

CGD

Zero-bias gate-drain junction capacitance

ACM = 0 : Farad
ACM = 1 :
Farad/Meter²

0.0

CGS

Zero-bias gate-source junction capacitance

ACM = 0 : Farad
ACM = 1 :
Farad/Meter²

0.0

CRAT

Source ratio of gate capacitance

None

0.666

D

Semiconductor dielectric constant

Silicon: 11.7
Gallium arsenide: 10.9

None

11.7

DCAP

Capacitance equation selector

None

2

DGAM

Dispersion model feedback coefficient

None

0.0

FC

Coefficient for PB in forward-bias capacitance calculations,
CAPOP = 0 or 2

None

0.5

GAMDS (GAMMA, GAMA)

Lowering coefficient for drain voltage-induced threshold voltage

None

0.0

GCAP

Zero-bias gate capacitance

ACM = 0 : Farad
ACM = 1 :
Farad/Meter²

Not used if not provided

GDSNOI

Channel noise coefficient (NLEV = 3)

None

1.0

HDIF

Distance of heavily-doped (low resistance) region from source or drain contact to lightly-doped region

Meter

0.0

IS

Gate junction saturation current.

ACM = 0: Amp
ACM = 1:
Amp/Meter²

1.0e-14

K1

Threshold voltage sensitivity to bulk node

Volt^½

0.0

KF

Flicker noise coefficient

None

0.0

L

FET gate length

Meter

0.0

LAMBDA (LAMB)

Channel length modulation factor

Must be 0 for Triquint TOM model compatibility.

Volt^-1

0.0

LAM1

Channel length modulation gate voltage parameter

Volt^-1

0.0

LDEL

Difference between drawn length and actual or optical device length

Meter

0.0

LDIF

Distance of lightly-doped region from heavily-doped region to transistor edge

Meter

0.0

MJ

Grading coefficient for gate-drain and gate-source diodes
(CAPOP = 0 or 2)

Step junction: 0.50
Linear graded junction: 0.33

None

0.50

N

Emission coefficient for gate-drain and gate-source diodes

None

1.0

NCHAN

Effective channel dopant concentration

atom/cm³

1.552e+22

ND

Drain subthreshold factor

Volt^-1

0.0

NG

Gate subthreshold factor

Volt^-1

0.0

NLEV

Noise equation selector

None

2

PB

Gate junction potential

Volt

0.8

RD

Drain ohmic resistance

Ohm

0.0

RG (RG2)

Gate ohmic resistance

Ohm

0.0

RS

Source ohmic resistance

Ohm

0.0

RSH

Sheet resistance of heavily-doped region

Ohm/square

0.0

RSHG

Gate sheet resistance

Ohm/square

0.0

SATEXP

Drain voltage exponent

None

3.0

TNOM

Nominal circuit temperature

°C

25

TT

Transit time

Second

0.0

UCRIT

Critical field for mobility degradation

Must be 0 for Triquint TOM model compatibility.

Volt/cm

0.0

VBI

Gate diode built-in voltage

Volt

1.0

VGEXP (Q)

Gate voltage exponent

None

2.0

VP

Pinch-off voltage

Volt

Calculated

VTO

Threshold voltage. If VTO is nonzero, it overrides the internal calculation.

Negative VTO denotes a depletion transistor (for both NJF and PJF), while positive VTO denotes an enhancement transistor.

Volt

Calculated

W

FET gate width

Meter

0.0

WDEL

Difference between drawn width and actual or optical device width

Meter

0.0