This document provides a model evaluation report for a Texas Instruments TL431 voltage regulator component. It includes the model parameters, SPICE simulation results comparing measured and simulated component characteristics, and evaluation circuits used for testing. Simulation results match measurements well with less than 10% error for most output and reference characteristics.

1. Model Evaluation Report
COMPONENTS: VOLTAGE REGULATOR
PART NUMBER: TL431
MANUFACTURER: Texas Instruments Incorporated
Panasonic
Bee Technologies Inc.
1

2. SPICE MODEL (1/2)
*$
* TL431
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* (C) Copyright 2009 Texas Instruments Incorporated. All rights reserved.
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` ** This model is designed as an aid for customers of Texas Instruments.
** TI and its licensors and suppliers make no warranties, either expressed
** or implied, with respect to this model, including the warranties of
** merchantability or fitness for a particular purpose. The model is
** provided solely on an "as is" basis. The entire risk as to its quality
** and performance is with the
customer
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*
* This model was developed for Texas Instruments Incorporated by:
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* This model is subject to change without notice. Neither Texas Instruments
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*
** Released by: Analog eLab Design Center, Texas Instruments Inc.
* Part: TL431
* Date: 12/14/2009
* Model Type: Transient and AC
* Simulator: PSPICE
* Simulator Version: 16.0.0.p001
* Datasheet: SLVS543J - AUGUST 2004 - REVISED DECEMBER 2005
*
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3. SPICE MODEL (2/2)
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*
* Updates:
*
* Final 2.00
` * Changed encrypted model to unencrypted.
*
* Final 1.00
* Release to Web.
*
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.SUBCKT TL431 7 6 11
* K A FDBK
V1 1 6 2.495
R1 6 2 15.6
C1 2 6 .5U
R2 2 3 100
C2 3 4 .08U
R3 4 6 10
GB1 6 8 VALUE = {IF(V(3,6)< 0 , 1.73*V(3,6) -1U , -1U)}
D1 5 8 DCLAMP
D2 7 8 DCLAMP
V4 5 6 2
G1 6 2 1 11 0.11
.MODEL DCLAMP D (IS=13.5N RS=25M N=1.59
+ CJO=45P VJ=.75 M=.302 TT=50.4N BV=34V IBV=1MA)
.ENDS
*$
3

4. CIRCUIT CONFIGURATION
K
FDBK
U1 TL431
A
MODEL PARAMETER
Pspice
model Model description
parameter
VREF Reference Voltage
N Emission Coefficient
BETA Tranconductance of JFET Transistor
VAF Early Voltage of Output Pass Transistor
CPZ Output Impedance Zero Capacitor
RB2 Base Resistance of Output Limit Voltage Source
ESC1 Coefficient of Current Limit Voltage Source
ESC2 Coefficient of Current Limit Voltage Source
EFB1 Coefficient of Foldback Current Voltage Source
EFB2 Coefficient of Foldback Current Voltage Source
EFB3 Coefficient of Foldback Current Voltage Source
EB Non-ideal Base-Collector Diode Saturation Current
4

5. Reference voltage Characteristic
Simulation Result
4.0V
3.0V
2.0V
1.0V
0s 20ms 40ms 60ms 80ms 100ms
V(KA)
Time
Evaluation Circuit
R1
KA
0.01m
I1 U1
10mAdc TL431
0
Comparison Table
Condition: VKA = Vref, IKA = 10 mA,
Parameter Measurement Simulation %Error
Vref(V) 2.495 2.498 0.14
5

6. Reference input current Characteristic
Simulation Result
1.0uA
0.5uA
0A
-0.5uA
-1.0uA
0s 20ms 40ms 60ms 80ms 100ms
I(U1:Fdbk)
Time
Evaluation Circuit
R1
KA
0.01m
R2
10k U1
I1 TL431
10mAdc
0
Comparison Table
Condition: IKA = 10 mA, R1 = 10 kΩ, R2 = ∞
Parameter Measurement Simulation %Error
Iref(uA) 2.000 0.000 -100.00
6

7. Off-state cathode current Characteristic
Simulation Result
4.0uA
2.0uA
0A
-2.0uA
0s 20ms 40ms 60ms 80ms 100ms
I(U1:K)
Time
Evaluation Circuit
V1
I1 TL431 U1 36Vdc
0Adc
0
Comparison Table
Condition: VKA = 36 V, Vref = 0,
Parameter Measurement Simulation %Error
Ioff(uA)[max] 1.000 1.541 54.13
7

8. Dynamic Impedance Characteristic
Simulation Result
2.53V
2.52V
2.51V
2.50V
2.49V
0A 20mA 40mA 60mA 80mA 100mA
V(R1:1)
I_I1
Evaluation Circuit
R1
KA
0.01m
I1 U1
0mAdc TL431
0
Comparison Table
Condition: VKA = Vref, IKA = 1 mA to 100 mA (|ZKA|=ΔV/Δi)
Parameter Measurement Simulation %Error
|ZKA| [Ω] 0.200 0.337 68.50
8

9. Output Characteristic
Simulation Result
2.0V
1.8V
1.6V
1.4V
1.2V
0A 20mA 40mA 60mA 80mA 100mA
V(U1:K)
I_I1
Evaluation Circuit
R1
I1
TL431 U1 100mAdc
1k
V1
3Vdc R2
1u
0
9

10. VKA Characteristic for VKA > Vref
Simulation Result
500mV
(53.769m,500.000m)
400mV
300mV
(55.489m,250.000m)
200mV
0s 20ms 40ms 60ms 80ms 100ms
V(Vo) V(U1:Fdbk)
Time
Evaluation Circuit
R1
Vo
10
R2
1
V1 TL431 U1
3Vdc
R3
1
0
Comparison Table
Condition: VKA=(1+R1/R2)*Vref=(1+1/1)*0.25=0.5
Parameter Measurement Simulation %Error
VKA 0.500 0.500 0.00
10