Transcript Changing Device Parameters in PSpice

Changing Device Parameters
in PSpice
Device Model: Diode
PSpice
• Simplest diode model in PSpice uses only the
ideal diode equation
• More complex diode models in PSpice
include:
– Parasitic resistances to account for the linear regions
– Breakdown voltage with current multipliers to map the
knee between Io and the current at breakdown
– Temperature dependences of various parameters
– Parasitic capacitances to account for the frequency
dependence
PSpice
• Device Simulation packages
– Capture
– Schematics
• The calculations performed will be identical when
using the same device models.
• The GUIs are not the same.
• There are minor differences in how the programs
interprets some changes that you make to the
device models.
PSpice Schematics
Device Parameters
*** Power Diode ***
Type of Diode
.MODEL D1N4002-X D
Part Number
( IS=14.11E-9
Reverse Saturation Current
N=1.984
Ideality Factor
RS=33.89E-3
Forward Series Resistance
IKF=94.81
High-Level Injection Knee Current in Forward Bias
XTI=3
Temperature Dependence of Reverse Saturation Current
EG=1.110
Energy Bandgap of Si
CJO=51.17E-12
Junction Capacitance at Zero Applied Bias
M=.2762
Grading Coefficient Inversely Proportional to Zener Resistance
VJ=.3905
Turn-on Voltage
FC=.5
Coefficient Associated with Forward Bias Capacitance
ISR=100.0E-12
Reverse Saturation Current During Reverse Bias
NR=2
Ideality Factor During Reverse Bias
BV=100.1
Breakdown Voltage
IBV=10
Current at Breakdown Voltage
TT=4.761E-6 )
Transit Time of Carriers Across p-n Juntion
PSpice Capture
Editing Device Model
• The device parameters can be changed, but will
only be changes for the file that you are currently
working on.
– In Schematics, the changes only apply to the specific
part that you had highlighted when you made the
changes.
– In Capture, the changes apply to all components in
the file that share the same part model.
– To simulate the Ideal Diode Equation, you can delete
the other parameters or set them to zero or a very
large number, depending on what would be
appropriate to remove their effect from the simulation