* SPICE netlist
Q1 N001 N004 N006 0 ZTX851
R1 N006 N009 1
XU1 N003 N001 +15 -15 N002 LT1028 ;pnba In+)In-)V+)V-)OUT
Q2 N010 N008 N009 0 ZTX851
XU2 N003 N010 +15 -15 N011 LT1028 ;pnba In+)In-)V+)V-)OUT
R2 +15 N001 1k
R3 +15 N010 1k
R4 vp N006 47
R5 vn N009 47
R6 N002 vp 220
R7 vn N011 220
R8 N004 0 220
R9 0 N008 220
XU3 N007 N005 +15 -15 Vo1 LT1028 ;pnba In+)In-)V+)V-)OUT
R10 Vo1 N005 250
R11 N005 vp 1k
R12 N007 vn 1k
R13 0 N007 250
V1 N004 N008 SINE(0 .0005 20e3 0 0 0 500) AC 1 Rser={Rser}
V2 +15 0 15
V3 0 -15 15
C1 N002 N001 390pF
C2 N011 N010 390pF
C3 N006 N004 390pF
C4 N009 N008 390pF
R14 +15 N003 1k
R15 N003 -15 3k
.four 20k V(Vo1)
.param plotwinsize = 0
.param numdgt = 15
.noise V(vo1) v1 dec 100 1 20E3
;ac dec 100 1 1000E6
.step param Rser 5 10 5
;tran 0 10e-3 2e-3 1e-6

* LTspice schematic (.asc)
Version 4
SHEET 1 1472 1184
WIRE 544 -560 544 -592
WIRE -160 -512 -288 -512
WIRE -48 -512 -160 -512
WIRE 544 -448 544 -480
WIRE 688 -448 544 -448
WIRE -288 -432 -288 -512
WIRE -160 -432 -160 -512
WIRE -48 -432 -48 -512
WIRE 544 -416 544 -448
WIRE 688 -400 688 -448
WIRE 128 -368 96 -368
WIRE 368 -368 192 -368
WIRE 544 -304 544 -336
WIRE -288 -240 -288 -352
WIRE 96 -240 96 -368
WIRE 96 -240 -288 -240
WIRE 208 -240 96 -240
WIRE 240 -240 240 -256
WIRE 368 -224 368 -368
WIRE 368 -224 272 -224
WIRE 208 -208 160 -208
WIRE 240 -176 240 -192
WIRE -160 -160 -160 -352
WIRE 160 -160 160 -208
WIRE 160 -160 -160 -160
WIRE -288 -144 -288 -240
WIRE 368 -128 368 -224
WIRE -544 -96 -736 -96
WIRE -416 -96 -544 -96
WIRE -352 -96 -416 -96
WIRE 576 -96 544 -96
WIRE 736 -96 656 -96
WIRE -544 -64 -544 -96
WIRE 736 -16 736 -96
WIRE -416 0 -416 -96
WIRE -384 0 -416 0
WIRE -288 0 -288 -48
WIRE -288 0 -320 0
WIRE 32 0 -288 0
WIRE 272 0 112 0
WIRE 368 0 368 -48
WIRE 368 0 272 0
WIRE 400 0 368 0
WIRE 544 0 544 -96
WIRE 544 0 480 0
WIRE -736 32 -736 -96
WIRE -544 48 -544 16
WIRE -448 48 -544 48
WIRE -288 48 -288 0
WIRE 544 64 544 0
WIRE 592 64 544 64
WIRE -448 80 -448 48
WIRE 736 80 736 -16
WIRE 736 80 656 80
WIRE 592 96 544 96
WIRE -544 112 -544 48
WIRE 400 112 368 112
WIRE 544 112 544 96
WIRE 544 112 480 112
WIRE -416 176 -448 176
WIRE -288 176 -288 128
WIRE -288 176 -352 176
WIRE 32 176 -288 176
WIRE 272 176 112 176
WIRE 368 176 368 112
WIRE 368 176 272 176
WIRE -288 208 -288 176
WIRE 544 208 544 112
WIRE -736 256 -736 112
WIRE -544 256 -544 192
WIRE -544 256 -736 256
WIRE -448 256 -448 176
WIRE -448 256 -544 256
WIRE -352 256 -448 256
WIRE 160 288 160 -160
WIRE 160 288 -144 288
WIRE 368 304 368 176
WIRE 544 320 544 288
WIRE -288 400 -288 304
WIRE -48 400 -48 -352
WIRE -48 400 -288 400
WIRE 96 400 -48 400
WIRE 208 400 96 400
WIRE 368 416 368 384
WIRE 368 416 272 416
WIRE 160 432 160 288
WIRE 208 432 160 432
WIRE -144 464 -144 288
WIRE -144 576 -144 544
WIRE 96 592 96 400
WIRE 144 592 96 592
WIRE 368 592 368 416
WIRE 368 592 208 592
FLAG 240 -256 +15
FLAG 240 -176 -15
FLAG 240 384 +15
FLAG 240 448 -15
FLAG -160 -512 +15
FLAG -448 80 0
FLAG 624 48 +15
FLAG 624 112 -15
FLAG 544 320 0
FLAG 736 -16 Vo1
FLAG 272 0 vp
FLAG 272 176 vn
FLAG 688 -400 0
FLAG 544 -592 +15
FLAG 544 -304 -15
FLAG -144 576 -15
SYMBOL npn -352 -144 R0
SYMATTR InstName Q1
SYMATTR Value ZTX851
SYMBOL res -304 32 R0
SYMATTR InstName R1
SYMATTR Value 1
SYMBOL Opamps\\LT1028 240 -288 R0
SYMATTR InstName U1
SYMBOL npn -352 304 M180
SYMATTR InstName Q2
SYMATTR Value ZTX851
SYMBOL Opamps\\LT1028 240 352 R0
SYMATTR InstName U2
SYMBOL res -304 -448 R0
SYMATTR InstName R2
SYMATTR Value 1k
SYMBOL res -64 -448 R0
SYMATTR InstName R3
SYMATTR Value 1k
SYMBOL res 128 -16 R90
SYMATTR InstName R4
SYMATTR Value 47
SYMBOL res 128 160 R90
SYMATTR InstName R5
SYMATTR Value 47
SYMBOL res 352 -144 R0
SYMATTR InstName R6
SYMATTR Value 220
SYMBOL res 352 288 R0
SYMATTR InstName R7
SYMATTR Value 220
SYMBOL res -560 -80 R0
SYMATTR InstName R8
SYMATTR Value 220
SYMBOL res -560 96 R0
SYMATTR InstName R9
SYMATTR Value 220
SYMBOL Opamps\\LT1028 624 16 R0
SYMATTR InstName U3
SYMBOL res 672 -112 R90
SYMATTR InstName R10
SYMATTR Value 250
SYMBOL res 496 -16 R90
SYMATTR InstName R11
SYMATTR Value 1k
SYMBOL res 496 96 R90
SYMATTR InstName R12
SYMATTR Value 1k
SYMBOL res 560 304 R180
SYMATTR InstName R13
SYMATTR Value 250
SYMBOL voltage -736 16 R0
SYMATTR InstName V1
SYMATTR Value SINE(0 .0005 20e3 0 0 0 500)
SYMATTR Value2 AC 1
SYMATTR SpiceLine Rser={Rser}
SYMBOL voltage 544 -576 R0
SYMATTR InstName V2
SYMATTR Value 15
SYMBOL voltage 544 -432 R0
SYMATTR InstName V3
SYMATTR Value 15
SYMBOL cap 192 -384 R90
SYMATTR InstName C1
SYMATTR Value 390pF
SYMBOL cap 208 576 R90
SYMATTR InstName C2
SYMATTR Value 390pF
SYMBOL cap -320 -16 R90
SYMATTR InstName C3
SYMATTR Value 390pF
SYMBOL cap -352 160 R90
SYMATTR InstName C4
SYMATTR Value 390pF
SYMBOL res -176 -448 R0
SYMATTR InstName R14
SYMATTR Value 1k
SYMBOL res -160 448 R0
SYMATTR InstName R15
SYMATTR Value 3k