pdks/sky130A/libs.tech/xschem/sky130_tests/tb_bandgap.sch

v {xschem version=3.0.0 file_version=1.2 

* Copyright 2021 Stefan Frederik Schippers
* 
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.

}
G {}
K {}
V {}
S {}
E {}
B 2 820 -310 1280 -70 {flags=graph
y1 = -2e-18
y2 = 1.8
divy = 5
x1=0
x2=0.00015
divx=5
node="vbg
en_n
start"
color="4 5 9" subdivx=4 unitx=u}
B 2 820 -450 1280 -320 {flags=graph
y1 = 0.96496
y2 = 1.30318
divy = 5
subdivy=1
x1=0
x2=0.00015
divx=4
subdivx=4
node="vbg"
color=7 unitx=u
}
B 2 820 -650 1280 -520 {flags=graph
y1 = 1.14744
y2 = 1.18232
divy = 5
subdivy=1
x1=0
x2=0.00015
divx=4
subdivx=4
node=vbg
color=8 unitx=u}
B 2 820 -880 1280 -750 {flags=graph
y1 = -4.2e-05
y2 = -6e-06
divy = 5
unity=u
subdivy=1
x1=0
x2=0.00015
divx=4
subdivx=4
node="\\"Icc;i(v2)\\"";i(v2)\\";i(v2)\\"
 unitx=u
color=4}
P 7 7 910 -480 910 -470 900 -470 910 -450 920 -470 910 -470 910 -480 {fill=true}
P 7 7 940 -480 940 -250 930 -250 940 -230 950 -250 940 -250 940 -480 {fill=true}
P 8 7 1070 -680 1070 -670 1060 -670 1070 -650 1080 -670 1070 -670 1070 -680 {fill=true}
P 8 7 1130 -680 1130 -250 1120 -250 1130 -230 1140 -250 1130 -250 1130 -680 {fill=true}
T {Example of Mismatch simulation of a 
bandgap reference. 
Variations are generated also on Vcc

Plot shows bandgap varying outputs before
and after the offset cancellation.
} 230 -880 0 0 0.4 0.4 {}
T {Select one or more graphs (and no other objects)
and use arrow keys to zoom / pan waveforms} 250 -610 0 0 0.3 0.3 {}
T {Bandgap voltage after offset compensation} 880 -700 0 0 0.3 0.3 {layer=8}
T {Bandgap voltage before offset compensation} 820 -500 0 0 0.3 0.3 {layer=7}
N 240 -340 240 -320 { lab=EN_N}
N 650 -340 650 -320 { lab=VCC}
N 390 -340 390 -320 { lab=VSS}
N 240 -220 240 -200 {lab=TEMPERAT}
N 390 -220 390 -200 { lab=START}
N 650 -220 650 -200 { lab=CLK}
C {devices/code.sym} 10 -450 0 0 {name=NGSPICE
only_toplevel=true
value="
* this experimental option enables mos model bin 
* selection based on W/NF instead of W
.options wnflag=1 XMU=0.49 METHOD=GEAR ITL4=100 CHGTOL=1e-15 TRTOL=1 RELTOL=0.0001 VNTOL=0.1u
.param ABSVAR=0.03
.param VCCGAUSS=agauss(1.8, 'ABSVAR', 1)
.param VCC=VCCGAUSS
* .param VCC=1.8
** variation marameters:
* .options savecurrents
.control
  option seed=12
  let run=1
  dowhile run <= 18
    if run > 1
      reset
      set appendwrite
    end
    save all
    if run % 3 = 0
      set temp=-40
    end
    if run % 3 = 1
      set temp=27
    end
    if run % 3 = 2
      set temp=125
    end
    tran 0.05u 150u
    write tb_bandgap.raw
    let run = run + 1
  end
  set nolegend
  plot all.vbg
.endc
" }
C {devices/title.sym} 160 -30 0 0 {name=l1 author="Stefan Schippers"}
C {sky130_tests/bandgap.sym} 410 -490 0 0 {name=x1}
C {devices/lab_pin.sym} 560 -530 0 1 {name=p1 lab=VBG}
C {devices/lab_pin.sym} 260 -490 0 0 {name=p2 lab=EN_N}
C {devices/vsource.sym} 240 -290 0 0 {name=V1 value=0}
C {devices/lab_pin.sym} 240 -340 0 1 {name=p3 lab=EN_N}
C {devices/vsource.sym} 650 -290 0 0 {name=V2 value="pwl 0 0 1u 0 4u VCC"}
C {devices/lab_pin.sym} 650 -340 0 1 {name=l29 sig_type=std_logic lab=VCC}
C {devices/lab_pin.sym} 260 -470 0 0 {name=p4 lab=VCC}
C {devices/lab_pin.sym} 260 -450 0 0 {name=p5 lab=VSS}
C {devices/vsource.sym} 390 -290 0 0 {name=V3 value=0}
C {devices/lab_pin.sym} 390 -340 0 1 {name=l3 sig_type=std_logic lab=VSS}
C {devices/lab_pin.sym} 240 -260 0 0 {name=l2 sig_type=std_logic lab=VSS}
C {devices/lab_pin.sym} 650 -260 0 0 {name=l4 sig_type=std_logic lab=VSS}
C {devices/lab_pin.sym} 390 -260 0 0 {name=l5 sig_type=std_logic lab=0}
C {devices/launcher.sym} 200 -90 0 0 {name=h2 
descr="Simulate" 
tclcommand="xschem netlist; xschem simulate"}
C {devices/vsource_arith.sym} 240 -170 0 0 {name=E5 VOL=temper MAX=200 MIN=-200}
C {devices/lab_pin.sym} 240 -220 0 1 {name=p113 lab=TEMPERAT}
C {devices/lab_pin.sym} 240 -140 0 0 {name=p114 lab=VSS}
C {devices/vsource.sym} 390 -170 0 0 {name=V4 value="pwl 0 VCC 25u VCC 25.001u 0"}
C {devices/lab_pin.sym} 390 -220 0 1 {name=p7 lab=START}
C {devices/lab_pin.sym} 390 -140 0 0 {name=l21 sig_type=std_logic lab=VSS}
C {devices/vsource.sym} 650 -170 0 0 {name=V5
value1="dc 0 "
value="dc 0 pulse 
+ VCC 0 
+ 25u
+ 1n 1n 
+ 27000n 30000n"
}
C {devices/lab_pin.sym} 650 -140 0 0 {name=l6 sig_type=std_logic lab=VSS}
C {devices/lab_pin.sym} 650 -220 0 1 {name=p6 lab=CLK}
C {devices/lab_pin.sym} 260 -530 0 0 {name=p8 lab=START}
C {devices/lab_pin.sym} 260 -510 0 0 {name=p9 lab=CLK}
C {devices/code.sym} 10 -250 0 0 {name=TT_MODELS
only_toplevel=true
format="tcleval( @value )"
value="
** opencircuitdesign pdks install
.lib $::SKYWATER_MODELS/sky130.lib.spice tt_mm

"
spice_ignore=false}
C {devices/launcher.sym} 235 -665 0 0 {name=h1 
descr="Select arrow and 
Ctrl-Left-Click to load/unload waveforms" 
tclcommand="
xschem raw_read $netlist_dir/[file tail [file rootname [xschem get current_name]]].raw
"
}