Download 1 Operating Point Information

HICUM
Operating Point Information
1 Operating Point Information
Below is a list of those quantities that should be provided by the circuit simulator to the model
user as “operating point information”. The voltages in the expressions are defined as follows:
VBEi= VB’ - VE’
VBEx = VB* - VE’
VBCi = VB’ - VC’
VBCx = VB* - VC’
VSCi = VS’ - VC’
Variable
Unit
IB
A
Base terminal current
as calculated in the model
IC
A
Collector terminal current
as calculated in the model
IS
A
Substrate terminal current
as calculated in the model
IAVL
A
Avalanche current
as calculated in the model
VBE
V
External BE voltage
as calculated in the model
VBC
V
External BC voltage
as calculated in the model
VCE
V
External CE voltage
as calculated in the model
VSC
V
External SC voltage
as calculated in the model
Common emitter forward current gain
IC
β dc = ----IB
BETADC
GMi
GMS
RPIi
© MS & AM
A/V
A/V
Ω
Description
Internal transconductance
(Same definition as for SGPM)
Transconductance of the parasitic substrate PNP
Internal base-emitter (input)
resistance
Definition
∂I T
g mi = -------------∂V BEi
∂I TS
g ms = --------------∂V BCx
∂I BEi
1- = ----------------∂V BEi
r πi
∂I T
= -------------∂V BEi
V CEi
V SCi
+
V BCi
∂I TS
– -------------∂V SCi
∂I T
------------∂V BCi
V BEi
V BCx
V BCi
1
HICUM
Operating Point Information
Variable
Unit
RPIx
Ω
Description
External base-emitter (input)
resistance
Definition
∂I BEp
1- = ------------------r πx
∂V BEx
∂I BEt
– --------------∂V BEx
V BCx
V BCx
(second term is due to tunnelling current)
RMUi
Ω
Internal feedback resistance
∂I BCi
1- = ----------------∂V BCi
r μi
V BEx
∂I AVL
– -------------∂V BCi
V BEi
(second term is due to avalanche current)
RMUx
ROi
Ω
Ω
External feedback resistance
Output resistance
∂I BCx
1 - = ------------------r μx
∂V BCx
∂I T
1
---= – -------------ro
∂V BCi
V BEx
V BEi
∂I AVL
+ -------------∂V BCi
V BEi
CPIi
F
Total internal BE capacitance
C πi = C jEi + C dE
CPIx
F
Total external BE capacitance
C πx = C jEp + C BEpar
CMUi
F
Total internal BC capacitance
C μi = C jCi + C dC
CMUx
F
Total external BC capacitance
C μx = C jCx + C BCpar + C dS
CCS
F
CS junction capacitance
C jS
RBI
Ω
Internal base resistance
as calculated in the model
RB
Ω
Total base resistance
as calculated in the model RBI + RBX
RCX
Ω
External (saturated) collector
series resistance
Model parameter RCX
RE
Ω
Emitter series resistance
Model parameter RE
Small signal current gain
β ac = g mi ⋅ ( r πi + r πx )
BETAAC
CRBI
F
Shunt capacitance across RBI
as calculated in the model
TF
s
Forward transit time
as calculated in the model
© MS & AM
2
HICUM
Operating Point Information
Variable
Unit
Description
FT
Hz
Transit frequency
(Note this is an approximation)
Definition
g mi
f T = ------------------------------------------------------------------------------ ,
2π ⋅ ( C BE + C BC + r ⋅ C BC ⋅ g mi )
C BE = C πi + C πx , C BC = C μi + C μx ,
RB + RE
r = R Cx + R E + ------------------ , R B = R BI + R BX
β ac
© MS & AM
3