* SPICE netlist
V1 +V 0 6.5
V2 0 -V 6.5
V3 N005 0 SINE(0 4 1k) AC 1
R1 N006 0 1Meg
R2 N006 N005 100
R3 N008 N007 2k
R4 bias N008 2k
V4 bias 0 4
V5 +5V 0 5
R5 N004 N009 2k
R6 N009 N010 2k
XU1 N006 N007 +V -V N007 TL072 ;pnba In+)In-)V+)V-)OUT
XU2 N008 N002 +5V 0 N002 AD8541 ;pnba In+)In-)V+)V-)OUT
XU3 N002 N003 +5V 0 N003 AD8541 ;pnba In+)In-)V+)V-)OUT
XU4 N003 N004 +5V 0 N004 AD8541 ;pnba In+)In-)V+)V-)OUT
XU5 bias/2 N009 +5V 0 N010 AD8541 ;pnba In+)In-)V+)V-)OUT
V6 bias/2 0 2
R7 N017 0 1Meg
R8 N017 N016 100
R9 N019 N018 2k
R10 bias N019 2k
R11 N015 N020 2k
R12 N020 N021 2k
XU6 N017 N018 +V -V N018 TL072 ;pnba In+)In-)V+)V-)OUT
XU7 N019 N012 +5V 0 N013 AD8541 ;pnba In+)In-)V+)V-)OUT
XU8 N013 N014 +5V 0 N014 AD8541 ;pnba In+)In-)V+)V-)OUT
XU9 N014 N015 +5V 0 N015 AD8541 ;pnba In+)In-)V+)V-)OUT
XU10 bias/2 N020 +5V 0 N021 AD8541 ;pnba In+)In-)V+)V-)OUT
V8 N016 0 SINE(0 2 1k) AC 1
R13 N013 N012 2k
R14 N012 bias/2 2k
R15 N029 0 1Meg
R16 N029 N028 100
R17 N031 N030 2k
R18 bias N031 2k
R19 N027 N032 2k
R20 N032 N033 2k
XU11 N029 N030 +V -V N030 TL072 ;pnba In+)In-)V+)V-)OUT
XU12 N031 N023 +5V 0 N024 AD8541 ;pnba In+)In-)V+)V-)OUT
XU13 N024 N025 +5V 0 N026 AD8541 ;pnba In+)In-)V+)V-)OUT
XU14 N026 N027 +5V 0 N027 AD8541 ;pnba In+)In-)V+)V-)OUT
XU15 bias/2 N032 +5V 0 N033 AD8541 ;pnba In+)In-)V+)V-)OUT
V7 N028 0 SINE(0 1 1k) AC 1
R21 N024 N023 2k
R22 N023 bias/2 2k
R23 N026 N025 2k
R24 N025 bias/2 2k
.tran 10m
.SUBCKT TL072 1 2 3 4 5
C1 11 12 3.498E-12
C2 6 7 15.00E-12
DC 5 53 DX
DE 54 5 DX
DLP 90 91 DX
DLN 92 90 DX
DP 4 3 DX
EGND 99 0 POLY(2) (3,0) (4,0) 0 .5 .5
FB 7 99 POLY(5) VB VC VE VLP VLN 0 4.715E6 -5E6 5E6 5E6 -5E6
GA 6 0 11 12 282.8E-6
GCM 0 6 10 99 8.942E-9
ISS 3 10 DC 195.0E-6
HLIM 90 0 VLIM 1K
J1 11 2 10 JX
J2 12 1 10 JX
R2 6 9 100.0E3
RD1 4 11 3.536E3
RD2 4 12 3.536E3
RO1 8 5 150
RO2 7 99 150
RP 3 4 2.143E3
RSS 10 99 1.026E6
VB 9 0 DC 0
VC 3 53 DC 2.200
VE 54 4 DC 2.200
VLIM 7 8 DC 0
VLP 91 0 DC 25
VLN 0 92 DC 25

* LTspice schematic (.asc)
Version 4
SHEET 1 2512 2992
WIRE 1256 -1496 -648 -1496
WIRE 568 -1400 424 -1400
WIRE 808 -1400 664 -1400
WIRE 1064 -1400 920 -1400
WIRE -904 -1352 -904 -1384
WIRE -904 -1352 -1000 -1352
WIRE 424 -1336 424 -1400
WIRE 456 -1336 424 -1336
WIRE 664 -1336 664 -1400
WIRE 696 -1336 664 -1336
WIRE 920 -1336 920 -1400
WIRE 952 -1336 920 -1336
WIRE -1000 -1320 -1000 -1352
WIRE -904 -1320 -904 -1352
WIRE -392 -1320 -536 -1320
WIRE -248 -1320 -312 -1320
WIRE -72 -1320 -248 -1320
WIRE 568 -1320 568 -1400
WIRE 568 -1320 520 -1320
WIRE 632 -1320 568 -1320
WIRE 808 -1320 808 -1400
WIRE 808 -1320 760 -1320
WIRE 872 -1320 808 -1320
WIRE 1064 -1320 1064 -1400
WIRE 1064 -1320 1016 -1320
WIRE 1176 -1320 1064 -1320
WIRE 40 -1304 -8 -1304
WIRE 136 -1304 40 -1304
WIRE 248 -1304 216 -1304
WIRE 456 -1304 248 -1304
WIRE 632 -1304 632 -1320
WIRE 696 -1304 632 -1304
WIRE 872 -1304 872 -1320
WIRE 952 -1304 872 -1304
WIRE -72 -1288 -104 -1288
WIRE -536 -1272 -536 -1320
WIRE -248 -1272 -248 -1320
WIRE 248 -1256 248 -1304
WIRE 1176 -1192 1176 -1320
WIRE 1176 -1192 856 -1192
WIRE -104 -1176 -104 -1288
WIRE 40 -1176 40 -1304
WIRE 40 -1176 -104 -1176
WIRE -536 -1160 -536 -1192
WIRE 856 -1080 856 -1192
WIRE 920 -1080 856 -1080
WIRE 1016 -1080 1000 -1080
WIRE 1048 -1080 1016 -1080
WIRE 1176 -1080 1128 -1080
WIRE 1016 -968 1016 -1080
WIRE 1048 -968 1016 -968
WIRE 1176 -952 1176 -1080
WIRE 1176 -952 1112 -952
WIRE 984 -936 968 -936
WIRE 1048 -936 984 -936
WIRE -648 -792 -648 -1496
WIRE 1256 -792 1256 -1496
WIRE 1256 -792 -648 -792
WIRE 1256 -584 -648 -584
WIRE 392 -456 344 -456
WIRE 424 -456 392 -456
WIRE 536 -456 504 -456
WIRE 776 -392 632 -392
WIRE 1032 -392 888 -392
WIRE 392 -328 392 -456
WIRE 424 -328 392 -328
WIRE 632 -328 632 -392
WIRE 664 -328 632 -328
WIRE 888 -328 888 -392
WIRE 920 -328 888 -328
WIRE -424 -312 -568 -312
WIRE -280 -312 -344 -312
WIRE -104 -312 -280 -312
WIRE 536 -312 536 -456
WIRE 536 -312 488 -312
WIRE 600 -312 536 -312
WIRE 776 -312 776 -392
WIRE 776 -312 728 -312
WIRE 840 -312 776 -312
WIRE 1032 -312 1032 -392
WIRE 1032 -312 984 -312
WIRE 1144 -312 1032 -312
WIRE 8 -296 -40 -296
WIRE 104 -296 8 -296
WIRE 216 -296 184 -296
WIRE 424 -296 216 -296
WIRE 600 -296 600 -312
WIRE 664 -296 600 -296
WIRE 840 -296 840 -312
WIRE 920 -296 840 -296
WIRE -104 -280 -136 -280
WIRE -568 -264 -568 -312
WIRE -280 -264 -280 -312
WIRE 216 -248 216 -296
WIRE 1144 -184 1144 -312
WIRE 1144 -184 824 -184
WIRE -136 -168 -136 -280
WIRE 8 -168 8 -296
WIRE 8 -168 -136 -168
WIRE -568 -152 -568 -184
WIRE 824 -72 824 -184
WIRE 888 -72 824 -72
WIRE 984 -72 968 -72
WIRE 1016 -72 984 -72
WIRE 1144 -72 1096 -72
WIRE 984 40 984 -72
WIRE 1016 40 984 40
WIRE 1144 56 1144 -72
WIRE 1144 56 1080 56
WIRE 952 72 936 72
WIRE 1016 72 952 72
WIRE -648 216 -648 -584
WIRE 1256 216 1256 -584
WIRE 1256 216 -648 216
WIRE 1256 520 -648 520
WIRE 392 808 392 760
WIRE 424 808 392 808
WIRE 536 808 504 808
WIRE 632 808 632 760
WIRE 664 808 632 808
WIRE 776 808 744 808
WIRE 1032 872 888 872
WIRE 392 936 392 808
WIRE 424 936 392 936
WIRE 632 936 632 808
WIRE 664 936 632 936
WIRE 888 936 888 872
WIRE 920 936 888 936
WIRE -424 952 -568 952
WIRE -280 952 -344 952
WIRE -104 952 -280 952
WIRE 536 952 536 808
WIRE 536 952 488 952
WIRE 600 952 536 952
WIRE 776 952 776 808
WIRE 776 952 728 952
WIRE 840 952 776 952
WIRE 1032 952 1032 872
WIRE 1032 952 984 952
WIRE 1144 952 1032 952
WIRE 8 968 -40 968
WIRE 104 968 8 968
WIRE 216 968 184 968
WIRE 424 968 216 968
WIRE 600 968 600 952
WIRE 664 968 600 968
WIRE 840 968 840 952
WIRE 920 968 840 968
WIRE -104 984 -136 984
WIRE -568 1000 -568 952
WIRE -280 1000 -280 952
WIRE 216 1016 216 968
WIRE 1144 1080 1144 952
WIRE 1144 1080 824 1080
WIRE -136 1096 -136 984
WIRE 8 1096 8 968
WIRE 8 1096 -136 1096
WIRE -568 1112 -568 1080
WIRE 824 1192 824 1080
WIRE 888 1192 824 1192
WIRE 984 1192 968 1192
WIRE 1016 1192 984 1192
WIRE 1144 1192 1096 1192
WIRE 984 1304 984 1192
WIRE 1016 1304 984 1304
WIRE 1144 1320 1144 1192
WIRE 1144 1320 1080 1320
WIRE 952 1336 936 1336
WIRE 1016 1336 952 1336
WIRE -648 1496 -648 520
WIRE 1256 1496 1256 520
WIRE 1256 1496 -648 1496
FLAG -1000 -1320 0
FLAG -904 -1464 +V
FLAG -904 -1240 -V
FLAG -40 -1272 +V
FLAG -40 -1336 -V
FLAG -536 -1160 0
FLAG -248 -1192 0
FLAG -1128 -1480 bias
FLAG -1128 -1400 0
FLAG 248 -1176 bias
FLAG 488 -1288 0
FLAG 728 -1288 0
FLAG -904 -1096 +5V
FLAG -904 -1016 0
FLAG 488 -1352 +5V
FLAG 728 -1352 +5V
FLAG 984 -1288 0
FLAG 984 -1352 +5V
FLAG 1080 -920 0
FLAG 1080 -984 +5V
FLAG -1256 -1480 bias/2
FLAG -1256 -1400 0
FLAG 984 -936 bias/2
FLAG -72 -264 +V
FLAG -72 -328 -V
FLAG -568 -152 0
FLAG -280 -184 0
FLAG 216 -168 bias
FLAG 456 -280 0
FLAG 696 -280 0
FLAG 456 -344 +5V
FLAG 696 -344 +5V
FLAG 952 -280 0
FLAG 952 -344 +5V
FLAG 1048 88 0
FLAG 1048 24 +5V
FLAG 952 72 bias/2
FLAG 264 -456 bias/2
FLAG -72 1000 +V
FLAG -72 936 -V
FLAG -568 1112 0
FLAG -280 1080 0
FLAG 216 1096 bias
FLAG 456 984 0
FLAG 696 984 0
FLAG 456 920 +5V
FLAG 696 920 +5V
FLAG 952 984 0
FLAG 952 920 +5V
FLAG 1048 1352 0
FLAG 1048 1288 +5V
FLAG 952 1336 bias/2
FLAG 392 680 bias/2
FLAG 632 680 bias/2
SYMBOL voltage -904 -1480 R0
SYMATTR InstName V1
SYMATTR Value 6.5
SYMBOL voltage -904 -1336 R0
SYMATTR InstName V2
SYMATTR Value 6.5
SYMBOL voltage -536 -1288 R0
SYMATTR Value2 AC 1
SYMATTR InstName V3
SYMATTR Value SINE(0 4 1k)
SYMBOL res -264 -1288 R0
SYMATTR InstName R1
SYMATTR Value 1Meg
SYMBOL res -296 -1336 R90
SYMATTR InstName R2
SYMATTR Value 100
SYMBOL res 232 -1320 R90
SYMATTR InstName R3
SYMATTR Value 2k
SYMBOL res 264 -1160 R180
SYMATTR InstName R4
SYMATTR Value 2k
SYMBOL voltage -1128 -1496 R0
SYMATTR InstName V4
SYMATTR Value 4
SYMBOL voltage -904 -1112 R0
SYMATTR InstName V5
SYMATTR Value 5
SYMBOL res 904 -1064 R270
SYMATTR InstName R5
SYMATTR Value 2k
SYMBOL res 1032 -1064 R270
SYMATTR InstName R6
SYMATTR Value 2k
SYMBOL OpAmps\\opamp2 -40 -1240 M180
SYMATTR InstName U1
SYMATTR Value TL072
SYMBOL OpAmps\\AD8541 488 -1384 R0
SYMATTR InstName U2
SYMBOL OpAmps\\AD8541 728 -1384 R0
SYMATTR InstName U3
SYMBOL OpAmps\\AD8541 984 -1384 R0
SYMATTR InstName U4
SYMBOL OpAmps\\AD8541 1080 -1016 R0
SYMATTR InstName U5
SYMBOL voltage -1256 -1496 R0
SYMATTR InstName V6
SYMATTR Value 2
SYMBOL res -296 -280 R0
SYMATTR InstName R7
SYMATTR Value 1Meg
SYMBOL res -328 -328 R90
SYMATTR InstName R8
SYMATTR Value 100
SYMBOL res 200 -312 R90
SYMATTR InstName R9
SYMATTR Value 2k
SYMBOL res 232 -152 R180
SYMATTR InstName R10
SYMATTR Value 2k
SYMBOL res 872 -56 R270
SYMATTR InstName R11
SYMATTR Value 2k
SYMBOL res 1000 -56 R270
SYMATTR InstName R12
SYMATTR Value 2k
SYMBOL OpAmps\\opamp2 -72 -232 M180
SYMATTR InstName U6
SYMATTR Value TL072
SYMBOL OpAmps\\AD8541 456 -376 R0
SYMATTR InstName U7
SYMBOL OpAmps\\AD8541 696 -376 R0
SYMATTR InstName U8
SYMBOL OpAmps\\AD8541 952 -376 R0
SYMATTR InstName U9
SYMBOL OpAmps\\AD8541 1048 -8 R0
SYMATTR InstName U10
SYMBOL voltage -568 -280 R0
SYMATTR Value2 AC 1
SYMATTR InstName V8
SYMATTR Value SINE(0 2 1k)
SYMBOL res 520 -472 R90
SYMATTR InstName R13
SYMATTR Value 2k
SYMBOL res 360 -472 R90
SYMATTR InstName R14
SYMATTR Value 2k
SYMBOL res -296 984 R0
SYMATTR InstName R15
SYMATTR Value 1Meg
SYMBOL res -328 936 R90
SYMATTR InstName R16
SYMATTR Value 100
SYMBOL res 200 952 R90
SYMATTR InstName R17
SYMATTR Value 2k
SYMBOL res 232 1112 R180
SYMATTR InstName R18
SYMATTR Value 2k
SYMBOL res 872 1208 R270
SYMATTR InstName R19
SYMATTR Value 2k
SYMBOL res 1000 1208 R270
SYMATTR InstName R20
SYMATTR Value 2k
SYMBOL OpAmps\\opamp2 -72 1032 M180
SYMATTR InstName U11
SYMATTR Value TL072
SYMBOL OpAmps\\AD8541 456 888 R0
SYMATTR InstName U12
SYMBOL OpAmps\\AD8541 696 888 R0
SYMATTR InstName U13
SYMBOL OpAmps\\AD8541 952 888 R0
SYMATTR InstName U14
SYMBOL OpAmps\\AD8541 1048 1256 R0
SYMATTR InstName U15
SYMBOL voltage -568 984 R0
SYMATTR Value2 AC 1
SYMATTR InstName V7
SYMATTR Value SINE(0 1 1k)
SYMBOL res 520 792 R90
SYMATTR InstName R21
SYMATTR Value 2k
SYMBOL res 408 776 R180
SYMATTR InstName R22
SYMATTR Value 2k
SYMBOL res 760 792 R90
SYMATTR InstName R23
SYMATTR Value 2k
SYMBOL res 648 776 R180
SYMATTR InstName R24
SYMATTR Value 2k