* SPICE netlist
V1 N003 0 400
R1 N004 N006 2Meg
R2 N006 0 25k
R3 N004 N007 2Meg
R7 N007 0 287k
D1 0 N008 KDZV36B
R10 N004 N008 100k
Vmicro N005 0 5V
R6 N008 N012 1.4Meg
R15 N012 0 200k
Rmicroin1 N002 0 100Meg
R17 N010 0 100k
R18 N005 N010 6.2k
XU1 N012 N010 N005 0 N002 LT1716 ;pnba In+)In-)V+)V-)OUT
M1 N003 N009 N004 N004 Si7489DP
D3 N009 N004 BZX84B10VLY
R4 N009 0 100k
R5 N013 0 100Meg
R9 N004 N011 1Meg
Q1 N011 N001 0 0 NPN
M2 N007 N011 N013 N013 2N7002
R8 N002 N001 100k
D2 0 N011 BZX84B10VLY
;tran 0 5 0 1
.dc V1 0 400 1

* LTspice schematic (.asc)
Version 4
SHEET 1 2768 640
WIRE 232 -304 -264 -304
WIRE 856 -304 312 -304
WIRE -1192 -176 -1384 -176
WIRE -968 -176 -1096 -176
WIRE -616 -176 -968 -176
WIRE -376 -176 -616 -176
WIRE -168 -176 -376 -176
WIRE 88 -176 -168 -176
WIRE -616 -144 -616 -176
WIRE -376 -144 -376 -176
WIRE -168 -128 -168 -176
WIRE -968 -96 -968 -176
WIRE 88 -80 88 -176
WIRE 1160 -16 712 -16
WIRE 1384 -16 1160 -16
WIRE -1384 0 -1384 -176
WIRE -616 0 -616 -64
WIRE -376 0 -376 -64
WIRE -40 0 -376 0
WIRE 1160 16 1160 -16
WIRE 88 32 88 0
WIRE 536 32 88 32
WIRE -1112 48 -1112 -128
WIRE -968 48 -968 -32
WIRE -968 48 -1112 48
WIRE -40 48 -40 0
WIRE 952 48 632 48
WIRE 712 96 712 -16
WIRE 1384 96 1384 -16
WIRE 88 112 88 32
WIRE 632 112 632 48
WIRE 680 112 632 112
WIRE -968 128 -968 48
WIRE -168 128 -168 -48
WIRE -104 128 -168 128
WIRE -88 128 -104 128
WIRE 856 128 856 -304
WIRE 856 128 744 128
WIRE 952 128 952 48
WIRE 1160 128 1160 96
WIRE 1160 128 952 128
WIRE -376 144 -376 0
WIRE 536 144 536 112
WIRE 680 144 536 144
WIRE 536 176 536 144
WIRE 856 176 856 128
WIRE 1160 176 1160 128
WIRE -168 192 -168 128
WIRE -104 208 -104 128
WIRE -40 224 -40 144
WIRE -264 240 -264 -304
WIRE -232 240 -264 240
WIRE -1384 304 -1384 80
WIRE -968 304 -968 208
WIRE -968 304 -1384 304
WIRE -616 304 -616 80
WIRE -616 304 -968 304
WIRE -376 304 -376 224
WIRE -376 304 -616 304
WIRE -168 304 -168 288
WIRE -168 304 -376 304
WIRE -104 304 -104 272
WIRE -104 304 -168 304
WIRE -40 304 -104 304
WIRE 88 304 88 176
WIRE 88 304 -40 304
WIRE 536 304 536 256
WIRE 712 304 712 160
WIRE 712 304 536 304
WIRE 856 304 856 256
WIRE 856 304 712 304
WIRE 1032 304 856 304
WIRE 1160 304 1160 256
WIRE 1160 304 1032 304
WIRE 1384 304 1384 176
WIRE 1384 304 1160 304
WIRE -616 320 -616 304
FLAG -616 320 0
FLAG 1032 304 0
SYMBOL voltage -1384 -16 R0
SYMATTR InstName V1
SYMATTR Value 400
SYMBOL res -632 -160 R0
SYMATTR InstName R1
SYMATTR Value 2Meg
SYMBOL res -632 -16 R0
SYMATTR InstName R2
SYMATTR Value 25k
SYMBOL res -392 -160 R0
SYMATTR InstName R3
SYMATTR Value 2Meg
SYMBOL res -392 128 R0
SYMATTR InstName R7
SYMATTR Value 287k
SYMBOL zener 104 176 R180
SYMATTR InstName D1
SYMATTR Value KDZV36B
SYMBOL res 72 -96 R0
SYMATTR InstName R10
SYMATTR Value 100k
SYMBOL voltage 1384 80 R0
SYMATTR InstName Vmicro
SYMATTR Value 5V
SYMBOL res 520 16 R0
SYMATTR InstName R6
SYMATTR Value 1.4Meg
SYMBOL res 520 160 R0
SYMATTR InstName R15
SYMATTR Value 200k
SYMBOL res 840 160 R0
SYMATTR InstName Rmicroin1
SYMATTR Value 100Meg
SYMBOL res 1144 160 R0
SYMATTR InstName R17
SYMATTR Value 100k
SYMBOL res 1144 0 R0
SYMATTR InstName R18
SYMATTR Value 6.2k
SYMBOL Comparators\\LT1716 712 128 R0
SYMATTR InstName U1
SYMBOL pmos -1192 -128 R270
SYMATTR InstName M1
SYMATTR Value Si7489DP
SYMBOL zener -952 -32 R180
SYMATTR InstName D3
SYMATTR Value BZX84B10VLY
SYMBOL res -984 112 R0
SYMATTR InstName R4
SYMATTR Value 100k
SYMBOL res -56 208 R0
SYMATTR InstName R5
SYMATTR Value 100Meg
SYMBOL res -184 -144 R0
SYMATTR InstName R9
SYMATTR Value 1Meg
SYMBOL npn -232 192 R0
SYMATTR InstName Q1
SYMBOL nmos -88 48 R0
SYMATTR InstName M2
SYMATTR Value 2N7002
SYMBOL res 328 -320 R90
SYMATTR InstName R8
SYMATTR Value 100k
SYMBOL zener -88 272 R180
SYMATTR InstName D2
SYMATTR Value BZX84B10VLY