Other Parts Discussed in Thread: TINA-TI, TL431,
Tool/software: TINA-TI or Spice Models
I am trying to get a SPICE simulation of the LM431 working properly. I have read that the TL431 model is similar. I have tried to use several different models from TI, including the latest release of the ATL431A_TRANS model. It is version 1.40 released 1/15/2019.
I have a test bench to make sure the model is working. The circuit is the same circuit as Figure 21 of the datasheet. The input is 48V, the reference is suppose to be set for 20V. Series resistor is 4.5k which would set the current to 10 mA, same as what is in the datasheet when measuring the reference . R1 is 10k and R2 is 1.487k.
Note that I am an experienced SPICE user and I am 100% sure I have the model set up properly. If I flip the canoed and cathode, I get a forward biased PN junction, as expected. If I simulate the circuit for Ioff in Figure 22, I don't get the right values. I have tried every pin order and none of them give results that match the datasheet.
What am I missing here?
I also tried to make this design in TINA, but it appears the shunt regulators are not built in?
Here is the model file I am using:
* ATL431A
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* (C) Copyright 2018 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
*****************************************************************************
*
* This model is subject to change without notice. Texas Instruments
* Incorporated is not responsible for updating this model.
*
*****************************************************************************
*
** Released by: Texas Instruments Inc.
* Part: ATL431A
* Date: 15JAN2019
* Model Type: TRANSIENT
* Simulator: PSPICE
* Simulator Version: 16.2.0.p001
* EVM Order Number: ATL431EVM
* EVM Users Guide: SLVUAE7 – April 2015
* Datasheet: SLVSCV5D –MARCH 2015–REVISED OCTOBER 2016
*
* Model Version: Final 1.40
*
*****************************************************************************
*
* Updates:
*
* Final 1.00
* Release to Web.
*
* Final 1.10
* Reference voltage kept at 2.5V DC
* Changed the Cathode reverse voltage from 2V to 1.5V
*
* Final 1.20
* AC Response modeled as per new datasheet
* Reference Input current modeled
*
* Final 1.30
* The IKA v/s VKA modeling changed
*
* Final 1.40
* 1. The main loop is kept same as TL431A
* 2. Model changes done to fix issue in Line transient
*
*****************************************************************************
*
* Model Usage Notes:
* 1. The following features have been modeled and Validated.
* a. Maximum Cathode Voltage.
* b. Minimum Cathode current for regulation.
* c. OFF STATE CATHODE CURRENT
* d. CATHODE VOLTAGE v/s CATHODE CURRENT
* e. PULSE RESPONSE
* f. Noise Analysis
* g. Reference Input Current
* h. Input Transient
* i. Regulation for negative supply
* j. Dynamic Impedance
* k. Open Loop Response
* l. Shunt Regulation behaviour
* 2. Temperature effects are not modeled.
* 3. AC analysis or loop behaviour is not modeled.
*
*****************************************************************************
.SUBCKT ATL431A_TRANS CATHODE REF ANODE
R_R1 6 2 15.6
E_E27 REF_INT 0 VALUE { IF(V(FB_INT,0)<2.45,V(FB_INT,0),V(1)) }
R_R10 E1 6 1
E_E1 N23666 6 2 6 1
E_ABM45 N15048350 0 VALUE { if(V(REF)>0,LIMIT(((V(B1)-V(E1))*7.2),2.5,0),0.004625) }
D_D11 5 8 DCLAMP
E_E28 FB_INT 0 REF 6 1
E_E31 1 0 N15048350 0 1
D_D12 7 8 DCLAMP
X_U6 REF N17052054 vnse
V_V1 N17052054 11 0Vdc
V_V2 5 6 2
R_R8 N15048182 N15048218 10
G_G4 6 2 REF_INT 11 110m
V_V3 7 CATHODE 0Vdc
V_V6 N15048182 6 100
V_V4 6 ANODE 0Vdc
R_R9 B1 REF 54Meg
C_C1 6 2 0.5u TC=0,0
G_ABM2I4 6 8 VALUE { LIMIT(IF((V(N23666)-V(6))< 0 , 1.73*(V(N23666)-V(6)) -0.037u, -0.037u),-100m,-8u*V(1,6)) }
X_U9 N15048218 B1 E1 bjt PARAMS:
.ENDS ATL431A_TRANS
*$
.model DCLAMP d
+ is=1.35e-008
+ rs=0.025
+ n=1.59
+ cjo=4.5e-011
+ vj=0.75
+ m=0.302
+ tt=5.04e-008
+ bv=34
+ ibv=0.001
*$
.subckt vnse 1 2
.PARAM NLF=1000
.PARAM FLW=13
.PARAM NVR=200
.PARAM GLF={PWR(FLW,0.25)*NLF/1164}
.PARAM RNV={1.184*PWR(NVR,2)}
.MODEL DVN D KF={15*PWR(FLW,0.2)/1E11} IS=1.0E-16
I1 0 7 10E-3
I2 0 8 10E-3
D1 7 0 DVN
D2 8 0 DVN
E1 3 6 7 8 {GLF}
R1 3 0 1E9
R2 3 0 1E9
R3 3 6 1E9
E2 6 4 5 0 10
R4 5 0 {RNV}
R5 5 0 {RNV}
R6 3 4 1E9
R7 4 0 1E9
E3 1 2 3 4 1
C1 1 0 1E-15
C2 2 0 1E-15
C3 1 2 1E-15
.ends vnse
*$
.subckt bjt 3 2 1
q1 3 2 1 npn_1
.model npn_1 npn
+ bf=450
+ is=1e-019
.ends bjt
*$
