diff --git a/modules/module_4_type_2_PLL/diff_Roscillator/schematic/differential_core.sch b/modules/module_4_type_2_PLL/diff_Roscillator/schematic/differential_core.sch
new file mode 100644
index 00000000..0dcc4282
--- /dev/null
+++ b/modules/module_4_type_2_PLL/diff_Roscillator/schematic/differential_core.sch
@@ -0,0 +1,82 @@
+v {xschem version=3.4.6 file_version=1.2}
+G {}
+K {}
+V {}
+S {}
+E {}
+N 150 -100 150 -50 {lab=#net1}
+N 280 -50 410 -50 {lab=#net1}
+N 410 -100 410 -50 {lab=#net1}
+N 280 -50 280 -20 {lab=#net1}
+N 150 -50 280 -50 {lab=#net1}
+N 150 -220 150 -160 {lab=Out-}
+N 410 -220 410 -160 {lab=Out+}
+N 150 -330 150 -290 {lab=vdd}
+N 410 -330 410 -290 {lab=vdd}
+N 280 -330 410 -330 {lab=vdd}
+N 80 -130 110 -130 {lab=In+}
+N 450 -130 480 -130 {lab=In-}
+N 150 -330 280 -330 {lab=vdd}
+N 280 -370 280 -330 {lab=vdd}
+N 150 -130 200 -130 {lab=gnd}
+N 360 -130 410 -130 {lab=gnd}
+N 0 -220 150 -220 {lab=Out-}
+N 150 -230 150 -220 {lab=Out-}
+N -0 -220 -0 -200 {lab=Out-}
+N -30 -220 0 -220 {lab=Out-}
+N -0 -140 -0 -120 {lab=gnd}
+N 410 -220 560 -220 {lab=Out+}
+N 560 -220 560 -200 {lab=Out+}
+N 560 -220 590 -220 {lab=Out+}
+N 560 -140 560 -120 {lab=gnd}
+N 410 -240 410 -220 {lab=Out+}
+N 280 40 280 60 {lab=gnd}
+C {sg13g2_pr/sg13_lv_nmos.sym} 430 -130 0 1 {name=M1
+l=0.26u
+w=2.6u
+ng=1
+m=1
+model=sg13_lv_nmos
+spiceprefix=X
+}
+C {sg13g2_pr/sg13_lv_nmos.sym} 130 -130 0 0 {name=M2
+l=0.26u
+w=2.6u
+ng=1
+m=1
+model=sg13_lv_nmos
+spiceprefix=X
+}
+C {res.sym} 150 -260 0 0 {name=R1
+value=5k
+footprint=1206
+device=resistor
+m=1}
+C {res.sym} 410 -260 0 0 {name=R2
+value=5k
+footprint=1206
+device=resistor
+m=1}
+C {ipin.sym} 80 -130 0 0 {name=p3 lab=In+}
+C {iopin.sym} 280 -370 2 0 {name=p5 lab=vdd}
+C {iopin.sym} 280 60 2 0 {name=p1 lab=gnd}
+C {lab_pin.sym} 360 -130 0 0 {name=p2 sig_type=std_logic lab=gnd}
+C {lab_pin.sym} 200 -130 2 0 {name=p6 sig_type=std_logic lab=gnd}
+C {capa.sym} 0 -170 0 0 {name=C1
+m=1
+value=0.5f
+footprint=1206
+device="ceramic capacitor"}
+C {lab_pin.sym} 0 -120 0 0 {name=p7 sig_type=std_logic lab=gnd}
+C {ipin.sym} 480 -130 0 1 {name=p8 lab=In-}
+C {capa.sym} 560 -170 0 1 {name=C2
+m=1
+value=0.5f
+footprint=1206
+device="ceramic capacitor"}
+C {lab_pin.sym} 560 -120 0 1 {name=p9 sig_type=std_logic lab=gnd}
+C {opin.sym} 590 -220 0 0 {name=p10 lab=Out+}
+C {opin.sym} -30 -220 0 1 {name=p11 lab=Out-}
+C {isource.sym} 280 10 0 0 {name=I0 value=200u}
+C {sg13g2_pr/annotate_fet_params.sym} 700 -230 0 0 {name=annot1 ref=M1}
+C {sg13g2_pr/annotate_fet_params.sym} 810 -230 0 0 {name=annot2 ref=M2}
diff --git a/modules/module_4_type_2_PLL/diff_Roscillator/schematic/differential_core.sym b/modules/module_4_type_2_PLL/diff_Roscillator/schematic/differential_core.sym
new file mode 100644
index 00000000..0fcc760d
--- /dev/null
+++ b/modules/module_4_type_2_PLL/diff_Roscillator/schematic/differential_core.sym
@@ -0,0 +1,30 @@
+v {xschem version=3.4.6 file_version=1.2}
+G {}
+K {type=subcircuit
+format="@name @pinlist @symname"
+template="name=x1"
+}
+V {}
+S {}
+E {}
+L 4 -20 40 0 40 {}
+L 4 -20 -40 0 -40 {}
+L 4 -150 -40 -130 -40 {}
+L 4 -150 40 -130 40 {}
+L 7 -100 -70 -100 -50 {}
+L 7 -100 50 -100 70 {}
+B 5 -102.5 -72.5 -97.5 -67.5 {name=vdd dir=inout}
+B 5 -2.5 37.5 2.5 42.5 {name=Out+ dir=out}
+B 5 -2.5 -42.5 2.5 -37.5 {name=Out- dir=out}
+B 5 -152.5 -42.5 -147.5 -37.5 {name=In+ dir=in}
+B 5 -152.5 37.5 -147.5 42.5 {name=In- dir=in}
+B 5 -102.5 67.5 -97.5 72.5 {name=gnd dir=inout}
+P 4 5 0 0 -130 -60 -130 60 0 0 0 0 {}
+T {@symname} -124.5 4 0 0 0.1 0.1 {}
+T {@name} -68.75 4.25 0 0 0.1 0.1 {}
+T {vdd} -105 -26 2 1 0.2 0.2 {}
+T {Out+} -25 36 0 1 0.2 0.2 {}
+T {Out-} -25 -44 0 1 0.2 0.2 {}
+T {In+} -125 -44 0 0 0.2 0.2 {}
+T {In-} -125 36 0 0 0.2 0.2 {}
+T {gnd} -105 44 2 1 0.2 0.2 {}
diff --git a/modules/module_4_type_2_PLL/diff_Roscillator/testbench/diff_oscillator_tb.sch b/modules/module_4_type_2_PLL/diff_Roscillator/testbench/diff_oscillator_tb.sch
new file mode 100644
index 00000000..96a4c078
--- /dev/null
+++ b/modules/module_4_type_2_PLL/diff_Roscillator/testbench/diff_oscillator_tb.sch
@@ -0,0 +1,117 @@
+v {xschem version=3.4.6 file_version=1.2}
+G {}
+K {}
+V {}
+S {}
+E {}
+B 2 1250 -560 2050 -160 {flags=graph
+y1=-0.59
+y2=1.3
+ypos1=0
+ypos2=2
+divy=5
+subdivy=1
+unity=1
+x1=0
+x2=2e-09
+divx=5
+subdivx=1
+xlabmag=1.0
+ylabmag=1.0
+dataset=-1
+unitx=1
+logx=0
+logy=0
+color="4 7 12"
+node="voplus
+vominus
+vo_diff"}
+N 650 -240 700 -240 {lab=#net1}
+N 650 -160 700 -160 {lab=#net2}
+N 850 -240 900 -240 {lab=#net3}
+N 850 -160 900 -160 {lab=#net4}
+N 550 -290 550 -270 {lab=vdd}
+N 750 -290 950 -290 {lab=vdd}
+N 950 -290 950 -270 {lab=vdd}
+N 750 -290 750 -270 {lab=vdd}
+N 550 -290 750 -290 {lab=vdd}
+N 550 -130 550 -110 {lab=GND}
+N 550 -110 750 -110 {lab=GND}
+N 750 -130 750 -110 {lab=GND}
+N 750 -110 950 -110 {lab=GND}
+N 950 -130 950 -110 {lab=GND}
+N 480 -240 500 -240 {lab=Voplus}
+N 480 -330 1070 -330 {lab=Voplus}
+N 1050 -240 1070 -240 {lab=Voplus}
+N 480 -330 480 -240 {lab=Voplus}
+N 1070 -330 1070 -240 {lab=Voplus}
+N 1070 -160 1070 -70 {lab=Vominus}
+N 1050 -160 1070 -160 {lab=Vominus}
+N 480 -160 500 -160 {lab=Vominus}
+N 480 -160 480 -70 {lab=Vominus}
+N 400 -130 400 -90 {lab=GND}
+N 480 -70 1070 -70 {lab=Vominus}
+N 400 -230 400 -190 {lab=vdd}
+C {differential_core.sym} 650 -200 0 0 {name=x1}
+C {differential_core.sym} 850 -200 0 0 {name=x2}
+C {differential_core.sym} 1050 -200 0 0 {name=x3}
+C {lab_pin.sym} 950 -290 2 0 {name=p1 sig_type=std_logic lab=vdd}
+C {vsource.sym} 400 -160 0 0 {name=V1 value=1.2 savecurrent=false}
+C {gnd.sym} 950 -110 0 0 {name=l1 lab=GND}
+C {gnd.sym} 400 -90 0 0 {name=l2 lab=GND}
+C {lab_pin.sym} 400 -230 2 0 {name=p2 sig_type=std_logic lab=vdd}
+C {opin.sym} 1070 -330 0 0 {name=p3 lab=Voplus}
+C {opin.sym} 1070 -70 2 1 {name=p4 lab=Vominus}
+C {code_shown.sym} 0 -450 0 0 {name=transient_tb only_toplevel=false
+value="
+.include diff_oscillator_tb.save
+.param temp=27
+.ic V(Voplus)=1.2
+.control
+save all 
+op
+write diff_oscillator_tb.raw
+set appendwrite
+tran 10p 2n
+save all
+let vo_diff = v(Voplus) - v(Vominus)
+write diff_oscillator_tb.raw
+
+.endc
+"}
+C {devices/code_shown.sym} 0 -110 0 0 {name=MODEL only_toplevel=true
+format="tcleval( @value )"
+value=".lib cornerMOSlv.lib mos_tt
+"}
+C {launcher.sym} 1310 -70 0 0 {name=h3
+descr=SimulateNGSPICE
+tclcommand="
+# Setup the default simulation commands if not already set up
+# for example by already launched simulations.
+set_sim_defaults
+puts $sim(spice,1,cmd) 
+
+# Change the Xyce command. In the spice category there are currently
+# 5 commands (0, 1, 2, 3, 4). Command 3 is the Xyce batch
+# you can get the number by querying $sim(spice,n)
+set sim(spice,1,cmd) \{ngspice  \\"$N\\" -a\}
+
+# change the simulator to be used (Xyce)
+set sim(spice,default) 0
+
+# Create FET and BIP .save file
+mkdir -p $netlist_dir
+write_data [save_params] $netlist_dir/[file rootname [file tail [xschem get current_name]]].save
+
+# run netlist and simulation
+xschem netlist
+simulate
+"}
+C {devices/launcher.sym} 1310 -110 0 0 {name=h1
+descr="OP annotate" 
+tclcommand="xschem annotate_op"
+}
+C {launcher.sym} 1310 -30 0 0 {name=h5
+descr="load waves" 
+tclcommand="xschem raw_read $netlist_dir/diff_oscillator_tb.raw tran"
+}
diff --git a/modules/module_4_type_2_PLL/diff_Roscillator/testbench/simulations/diff_oscillator_tb.save b/modules/module_4_type_2_PLL/diff_Roscillator/testbench/simulations/diff_oscillator_tb.save
new file mode 100644
index 00000000..50debb58
--- /dev/null
+++ b/modules/module_4_type_2_PLL/diff_Roscillator/testbench/simulations/diff_oscillator_tb.save
@@ -0,0 +1,62 @@
+* Place this .save file with a .include line in your testbench
+
+.save @n.x1.xm1.nsg13_lv_nmos[ids]
+.save @n.x1.xm1.nsg13_lv_nmos[gm]
+.save @n.x1.xm1.nsg13_lv_nmos[gds]
+.save @n.x1.xm1.nsg13_lv_nmos[vth]
+.save @n.x1.xm1.nsg13_lv_nmos[vgs]
+.save @n.x1.xm1.nsg13_lv_nmos[vdss]
+.save @n.x1.xm1.nsg13_lv_nmos[vds]
+.save @n.x1.xm1.nsg13_lv_nmos[cgg]
+.save @n.x1.xm1.nsg13_lv_nmos[cgsol]
+.save @n.x1.xm1.nsg13_lv_nmos[cgdol]
+.save @n.x1.xm2.nsg13_lv_nmos[ids]
+.save @n.x1.xm2.nsg13_lv_nmos[gm]
+.save @n.x1.xm2.nsg13_lv_nmos[gds]
+.save @n.x1.xm2.nsg13_lv_nmos[vth]
+.save @n.x1.xm2.nsg13_lv_nmos[vgs]
+.save @n.x1.xm2.nsg13_lv_nmos[vdss]
+.save @n.x1.xm2.nsg13_lv_nmos[vds]
+.save @n.x1.xm2.nsg13_lv_nmos[cgg]
+.save @n.x1.xm2.nsg13_lv_nmos[cgsol]
+.save @n.x1.xm2.nsg13_lv_nmos[cgdol]
+.save @n.x2.xm1.nsg13_lv_nmos[ids]
+.save @n.x2.xm1.nsg13_lv_nmos[gm]
+.save @n.x2.xm1.nsg13_lv_nmos[gds]
+.save @n.x2.xm1.nsg13_lv_nmos[vth]
+.save @n.x2.xm1.nsg13_lv_nmos[vgs]
+.save @n.x2.xm1.nsg13_lv_nmos[vdss]
+.save @n.x2.xm1.nsg13_lv_nmos[vds]
+.save @n.x2.xm1.nsg13_lv_nmos[cgg]
+.save @n.x2.xm1.nsg13_lv_nmos[cgsol]
+.save @n.x2.xm1.nsg13_lv_nmos[cgdol]
+.save @n.x2.xm2.nsg13_lv_nmos[ids]
+.save @n.x2.xm2.nsg13_lv_nmos[gm]
+.save @n.x2.xm2.nsg13_lv_nmos[gds]
+.save @n.x2.xm2.nsg13_lv_nmos[vth]
+.save @n.x2.xm2.nsg13_lv_nmos[vgs]
+.save @n.x2.xm2.nsg13_lv_nmos[vdss]
+.save @n.x2.xm2.nsg13_lv_nmos[vds]
+.save @n.x2.xm2.nsg13_lv_nmos[cgg]
+.save @n.x2.xm2.nsg13_lv_nmos[cgsol]
+.save @n.x2.xm2.nsg13_lv_nmos[cgdol]
+.save @n.x3.xm1.nsg13_lv_nmos[ids]
+.save @n.x3.xm1.nsg13_lv_nmos[gm]
+.save @n.x3.xm1.nsg13_lv_nmos[gds]
+.save @n.x3.xm1.nsg13_lv_nmos[vth]
+.save @n.x3.xm1.nsg13_lv_nmos[vgs]
+.save @n.x3.xm1.nsg13_lv_nmos[vdss]
+.save @n.x3.xm1.nsg13_lv_nmos[vds]
+.save @n.x3.xm1.nsg13_lv_nmos[cgg]
+.save @n.x3.xm1.nsg13_lv_nmos[cgsol]
+.save @n.x3.xm1.nsg13_lv_nmos[cgdol]
+.save @n.x3.xm2.nsg13_lv_nmos[ids]
+.save @n.x3.xm2.nsg13_lv_nmos[gm]
+.save @n.x3.xm2.nsg13_lv_nmos[gds]
+.save @n.x3.xm2.nsg13_lv_nmos[vth]
+.save @n.x3.xm2.nsg13_lv_nmos[vgs]
+.save @n.x3.xm2.nsg13_lv_nmos[vdss]
+.save @n.x3.xm2.nsg13_lv_nmos[vds]
+.save @n.x3.xm2.nsg13_lv_nmos[cgg]
+.save @n.x3.xm2.nsg13_lv_nmos[cgsol]
+.save @n.x3.xm2.nsg13_lv_nmos[cgdol]
diff --git a/modules/module_4_type_2_PLL/diff_Roscillator/testbench/xschemrc b/modules/module_4_type_2_PLL/diff_Roscillator/testbench/xschemrc
new file mode 100644
index 00000000..795ca780
--- /dev/null
+++ b/modules/module_4_type_2_PLL/diff_Roscillator/testbench/xschemrc
@@ -0,0 +1,18 @@
+# xschemrc - Custom configuration file for xschem
+# This file sources another xschemrc file from a known location
+
+# Source the base configuration from a known location
+source $::env(PDK_ROOT)/$::env(PDK)/libs.tech/xschem/xschemrc
+
+# (Optional) Add any custom overrides or extensions below
+# set xschem_library_path /home/user/my_libs
+# set xschem_gui_font "Monospace 10"
+
+#### include skywater libraries. Here I use [pwd]. This works if I start xschem from here.
+###only if you dont have this setup already ### 
+###append XSCHEM_LIBRARY_PATH :[file dirname [info script]]
+
+
+#### Add custom libraries (directories with .lib files)
+append XSCHEM_LIBRARY_PATH :../schematic/
+