comparing various comparator topologies

comparator/comparator-preamp-selfbias.spice

diff --git a/comparator/comparator-preamp-selfbias.spice b/comparator/comparator-preamp-selfbias.spice
new file mode 100644
index 0000000..2dac93e
--- /dev/null
+++ b/comparator/comparator-preamp-selfbias.spice
@@ -0,0 +1,33 @@
+* scale: 1e6 units = 1 micron
+
+.subckt comparator-preamp-selfbias VP VN VPAMP VNAMP VGND VPWR
+
+*constant current source: paralleled to allow for size matching
+* X0 VI VI VGND VGND sky130_fd_pr__nfet_03v3_nvt w=1e+6u l=0.6e+6u
+* X1 VI VI VGND VGND sky130_fd_pr__nfet_03v3_nvt w=1e+6u l=0.6e+6u
+* 
+* *Diff Pair
+* X12 VPAMP VP VI VGND sky130_fd_pr__nfet_03v3_nvt w=1e+6u l=0.6e+6u
+* X13 VNAMP VN VI VGND sky130_fd_pr__nfet_03v3_nvt w=1e+6u l=0.6e+6u
+* 
+* *Load transistors
+* X24 VPWR VPAMP VPAMP VPWR sky130_fd_pr__pfet_g5v0d10v5 w=1.5e+6u l=0.5e+6u
+* X25 VPWR VNAMP VNAMP VPWR sky130_fd_pr__pfet_g5v0d10v5 w=1.5e+6u l=0.5e+6u
+
+* extracted
+*.option scale=1u
+
+
+X2 VPAMP VPAMP VPWR VPWR sky130_fd_pr__pfet_g5v0d10v5 ad=0 pd=0 as=-0 ps=0 w=1.5e+06u l=500000u
+X3 VNAMP VPAMP VPWR VPWR sky130_fd_pr__pfet_g5v0d10v5 ad=0 pd=0 as=-0 ps=0 w=1.5e+06u l=500000u
+
+X4 VGND VI VI VGND sky130_fd_pr__nfet_03v3_nvt ad=0 pd=0 as=-0 ps=0 w=1e+06u l=600000u
+X5 VGND VGND VGND VGND sky130_fd_pr__nfet_03v3_nvt ad=0 pd=0 as=0 ps=0 w=1e+06u l=600000u
+X6 VI VI VGND VGND sky130_fd_pr__nfet_03v3_nvt ad=-0 pd=0 as=0 ps=0 w=1e+06u l=600000u
+
+X12 VI VN VNAMP VGND sky130_fd_pr__nfet_03v3_nvt ad=-0 pd=0 as=-0 ps=0 w=1e+06u l=600000u
+X13 VI VP VPAMP VGND sky130_fd_pr__nfet_03v3_nvt ad=-0 pd=0 as=-0 ps=0 w=1e+06u l=600000u
+C0 VPWR VGND 8.16fF
+
+
+.ends
\ No newline at end of file

comparator/simulation.spice

diff --git a/comparator/simulation.spice b/comparator/simulation.spice
index ac9e253..3e93e5f 100644
--- a/comparator/simulation.spice
+++ b/comparator/simulation.spice
@@ -5,11 +5,16 @@
 .include comparator-decision.spice
 .include comparator-diffamp.spice
 .include comparator-whole.spice
+.include comparator-preamp-selfbias.spice
 
 * instantiate the comparator
-*Xpre VP VN VPAMP VNAMP VI BIASN VGND VPWR comparator-preamp
-*Xdec VPAMP VNAMP VOP VON VGND VPWR comparator-decision
-Xdif VP VN VOUTdiff VGND VDD1v8 comparator-diffamp
+*Xpre VP VN VPAMP VNAMP VI BIASN VGND VDD3v3 comparator-preamp
+Xpre VP VN VPAMP VNAMP VGND VDD3v3 comparator-preamp-selfbias
+Xdec VPAMP VNAMP VOP VON VGND VDD3v3 comparator-decision
+Xdif VOP VON VOUTdiff VGND VDD1v8 comparator-diffamp
+
+Xpuredif VP VN VOUTpurediff VGND VDD1v8 comparator-diffamp
+
 
 Xcomp VP VN BIASN VOUT VGND VDD3v3 VDD1v8 comparator-whole
 
@@ -36,7 +41,8 @@
 run
 set color0 = white
 set color1 = black
-plot VP VN VOUT VOUTdiff VDD3v3 
+plot VOUT VOUTdiff VDD3v3
+plot VOUTdiff VOUTpurediff VDD3v3
 *plot VPAMP VNAMP VI
 *plot VOP VON
 plot i(Vdd3v3) i(Vdd1v8)