* SPICE netlist
Mn2 vbn vbn 0 0 NMOS-SH l=1u w=10u
Mp2 N001 vbp VDD VDD PMOS-SH l=1u w=10u
Mn1 N004 vbn N005 0 NMOS-SH l=1u w=40u
R1 N005 0 {RB}
VDD VDD 0 3
Mp1 vbp vbp VDD VDD PMOS-SH l=1u w=10u
R2 N002 0 1G
Mn3 N003 N003 vbn 0 NMOS-SH l=1u w=10u
Mn4 N002 N003 N004 0 NMOS-SH l=1u w=10u
Mp3 N003 N002 N001 VDD PMOS-SH l=1u w=10u
Mp4 N002 N002 vbp VDD PMOS-SH l=1u w=10u
Mn5 vbn_simple vbn_simple 0 0 NMOS-SH l=1u w=10u
Mp5 vbn_simple vbp_simple VDD VDD PMOS-SH l=1u w=10u
Mn6 vbp_simple vbn_simple N006 0 NMOS-SH l=1u w=40u
R3 N006 0 {RB}
Mp6 vbp_simple vbp_simple VDD VDD PMOS-SH l=1u w=10u
R4 vbp_simple 0 1G
.param RB 2.29k
;.step param RB 500 2.5k 10
.dc VDD 0 4

* LTspice schematic (.asc)
Version 4
SHEET 1 1920 992
WIRE -624 -496 -960 -496
WIRE -544 -496 -624 -496
WIRE -432 -496 -544 -496
WIRE -80 -496 -432 -496
WIRE -16 -496 -80 -496
WIRE -544 -432 -544 -496
WIRE -80 -432 -80 -496
WIRE -384 -416 -496 -416
WIRE -128 -416 -384 -416
WIRE -624 -384 -624 -496
WIRE -544 -384 -624 -384
WIRE -16 -384 -16 -496
WIRE -16 -384 -80 -384
WIRE -544 -288 -544 -336
WIRE -480 -288 -544 -288
WIRE -384 -288 -384 -416
WIRE -384 -288 -480 -288
WIRE -544 -240 -544 -288
WIRE -80 -240 -80 -336
WIRE 432 -240 352 -240
WIRE 544 -240 432 -240
WIRE 896 -240 544 -240
WIRE 960 -240 896 -240
WIRE -384 -224 -496 -224
WIRE -128 -224 -384 -224
WIRE -624 -192 -624 -384
WIRE -544 -192 -624 -192
WIRE -16 -192 -16 -384
WIRE -16 -192 -80 -192
WIRE 432 -176 432 -240
WIRE 896 -176 896 -240
WIRE -960 -160 -960 -496
WIRE 592 -160 480 -160
WIRE 848 -160 592 -160
WIRE 352 -128 352 -240
WIRE 432 -128 352 -128
WIRE 960 -128 960 -240
WIRE 960 -128 896 -128
WIRE -544 -112 -544 -144
WIRE -384 -112 -384 -224
WIRE -384 -112 -544 -112
WIRE -80 -64 -80 -144
WIRE -80 -64 -256 -64
WIRE -544 -48 -544 -112
WIRE -544 -48 -800 -48
WIRE -544 -16 -544 -48
WIRE -80 -16 -80 -64
WIRE 432 -16 432 -80
WIRE 496 -16 432 -16
WIRE 592 -16 592 -160
WIRE 592 -16 496 -16
WIRE -544 32 -624 32
WIRE -16 32 -80 32
WIRE -256 64 -256 -64
WIRE -256 64 -496 64
WIRE -128 64 -256 64
WIRE 432 80 432 -16
WIRE 432 80 176 80
WIRE -800 96 -800 -48
WIRE -176 128 -256 128
WIRE -80 128 -80 80
WIRE -80 128 -176 128
WIRE 800 128 720 128
WIRE 896 128 896 -80
WIRE 896 128 800 128
WIRE -544 160 -544 80
WIRE -80 160 -80 128
WIRE 432 160 432 80
WIRE 896 160 896 128
WIRE -624 208 -624 32
WIRE -544 208 -624 208
WIRE -16 208 -16 32
WIRE -16 208 -80 208
WIRE 176 208 176 80
WIRE 432 208 352 208
WIRE 960 208 896 208
WIRE -256 240 -256 128
WIRE -256 240 -496 240
WIRE -128 240 -256 240
WIRE 720 240 720 128
WIRE 720 240 480 240
WIRE 848 240 720 240
WIRE -544 304 -544 256
WIRE 432 304 432 256
WIRE -960 448 -960 -80
WIRE -800 448 -800 176
WIRE -800 448 -960 448
WIRE -624 448 -624 208
WIRE -624 448 -800 448
WIRE -544 448 -544 384
WIRE -544 448 -624 448
WIRE -80 448 -80 256
WIRE -80 448 -544 448
WIRE -16 448 -16 208
WIRE -16 448 -80 448
WIRE 176 448 176 288
WIRE 176 448 -16 448
WIRE 352 448 352 208
WIRE 352 448 176 448
WIRE 432 448 432 384
WIRE 432 448 352 448
WIRE 896 448 896 256
WIRE 896 448 432 448
WIRE 960 448 960 208
WIRE 960 448 896 448
WIRE -960 496 -960 448
FLAG -960 496 0
FLAG -432 -496 VDD
FLAG -480 -288 vbp
FLAG -176 128 vbn
FLAG 544 -240 VDD
FLAG 496 -16 vbp_simple
FLAG 800 128 vbn_simple
SYMBOL nmos4 -128 160 R0
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mn2
SYMATTR Value NMOS-SH
SYMBOL pmos4 -128 -336 M180
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mp2
SYMATTR Value PMOS-SH
SYMBOL nmos4 -496 160 M0
SYMATTR Value2 l=1u w=40u
SYMATTR InstName Mn1
SYMATTR Value NMOS-SH
SYMBOL res -560 288 R0
SYMATTR InstName R1
SYMATTR Value {RB}
SYMBOL voltage -960 -176 R0
SYMATTR InstName VDD
SYMATTR Value 3
SYMBOL pmos4 -496 -336 R180
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mp1
SYMATTR Value PMOS-SH
SYMBOL res -816 80 R0
SYMATTR InstName R2
SYMATTR Value 1G
SYMBOL nmos4 -128 -16 R0
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mn3
SYMATTR Value NMOS-SH
SYMBOL nmos4 -496 -16 M0
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mn4
SYMATTR Value NMOS-SH
SYMBOL pmos4 -128 -144 M180
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mp3
SYMATTR Value PMOS-SH
SYMBOL pmos4 -496 -144 R180
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mp4
SYMATTR Value PMOS-SH
SYMBOL nmos4 848 160 R0
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mn5
SYMATTR Value NMOS-SH
SYMBOL pmos4 848 -80 M180
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mp5
SYMATTR Value PMOS-SH
SYMBOL nmos4 480 160 M0
SYMATTR Value2 l=1u w=40u
SYMATTR InstName Mn6
SYMATTR Value NMOS-SH
SYMBOL res 416 288 R0
SYMATTR InstName R3
SYMATTR Value {RB}
SYMBOL pmos4 480 -80 R180
SYMATTR Value2 l=1u w=10u
SYMATTR InstName Mp6
SYMATTR Value PMOS-SH
SYMBOL res 160 192 R0
SYMATTR InstName R4
SYMATTR Value 1G