Version 4
SHEET 1 1608 1700
WIRE -144 128 -336 128
WIRE 96 128 -64 128
WIRE 256 128 96 128
WIRE 400 128 256 128
WIRE 448 128 400 128
WIRE 96 144 96 128
WIRE 256 208 256 128
WIRE 400 224 400 128
WIRE -336 240 -336 128
WIRE 96 240 96 224
WIRE 224 240 96 240
WIRE 96 272 96 240
WIRE -336 400 -336 320
WIRE 96 400 96 352
WIRE 256 400 256 272
WIRE 400 400 400 288
FLAG 256 400 0
FLAG -336 400 0
FLAG 448 128 out
IOPIN 448 128 Out
FLAG -336 128 v1
FLAG 400 400 0
FLAG 96 400 0
SYMBOL res -160 144 R270
WINDOW 0 32 56 VTop 0
WINDOW 3 0 56 VBottom 0
SYMATTR InstName R1
SYMATTR Value 5k
SYMBOL voltage -336 224 R0
WINDOW 123 24 132 Left 0
WINDOW 39 0 0 Left 0
SYMATTR Value2 AC 1
SYMATTR InstName V1
SYMATTR Value PULSE(12.5 0 1m 1n 1n 5m 10m)
SYMBOL cap 384 224 R0
SYMATTR InstName C7
SYMATTR Value 100p
SYMBOL res 80 128 R0
SYMATTR InstName R2
SYMATTR Value 5m
SYMBOL res 80 256 R0
SYMATTR InstName R3
SYMATTR Value 5k
SYMBOL Robertugo\\xref3 240 208 R0
WINDOW 38 77 64 Center 0
SYMATTR SpiceModel TLV431AS
SYMATTR InstName U1
TEXT -360 -192 Left 0 !.op
TEXT -360 -160 Left 0 !.dc V1 -10 12.5 0.01
TEXT -360 -96 Left 0 ;.tran 0 12m 0 1u
TEXT -360 -32 Left 0 ;.noise v(out) v1 dec 100 10 10k
TEXT -360 -128 Left 0 ;.step TEMP 0 100 5
TEXT -360 -64 Left 0 ;.ac dec 100 1k 10MEG
TEXT -376 -488 Left 0 ;TLV431 Test Schematic\n \nThe model from Onsemi only works for Vout > 1.8V.\nModel changed to get voltages down to 1.25V:\n*V4 5 6 2\nV4 5 6 1.2
TEXT 288 -504 Left 0 ;.SUBCKT TLV431 7 6 11\n*             K A FDBK\n.MODEL DCLAMP D (IS=13.5N RS=25M N=1.59 \n+ CJO=45P VJ=.75 M=.302 TT=50.4N BV=36V IBV=1MA)\n.MODEL DCL2 D RS=660K\nV1 1 6 1.24\nR1 6 2 15.6\nC1 2 6 .5U\nR2 2 3 100\nC2 3 4 1.3U\nR3 4 6 8\nG2 6 8 3 6  .86\nD1 5 8 DCLAMP\nD2 7 8 DCLAMP\nD4 6 8 DCLAMP\n*V4 5 6 2\nV4 5 6 1.2\nG1 6 2 1 11 0.11\nVCLAMP 9 6 14.5\nD3  7 9 DCL2\n.ENDS