Common Source Amplifier

Transient analysis of Common Source Amplifier (tran)

Testbench

*TB_SUN_TR_SKY130NM/TB_NCM

*-----------------------------------------------------------------
* OPTIONS
*-----------------------------------------------------------------
.option TNOM=27 GMIN=1e-15 reltol=1e-3

*-----------------------------------------------------------------
* PARAMETERS
*-----------------------------------------------------------------

.param AVDD = {vdda}

*-----------------------------------------------------------------
* FORCE
*-----------------------------------------------------------------
VSS  VSS  0     dc 0
VDD  VDD_1V8  0  dc 0 pwl 0 0 10n {AVDD}


VIN VIN 0 dc 0 sin (0 10m 1G 1u 0 0 )

*- Make a bias source
R1 VDD_1V8 VBIAS 10k
XM1 VBIAS VBIAS VSS VSS sky130_fd_pr__nfet_01v8 L=0.2 W=1
R2 VBIAS VG 1k

*- Common source amplifier
C1 VIN VG 1p
R3 VDD_1V8 VOUT 1k
XM2 VOUT VG VSS VSS sky130_fd_pr__nfet_01v8 L=0.2 W=1 M=10

*----------------------------------------------------------------
* NGSPICE control
*----------------------------------------------------------------
.control
set num_threads=8
set color0=white
set color1=black
unset askquit

optran 0 0 0 1n 100n 0
tran 100p 1.1u 1.09u
write
quit

.endc

.end

Measurements

* Measure nmos
.control

load {cicname}.raw

echo "MEAS_START"

meas tran vpp_vin PP v(vin)
meas tran vpp_vg PP v(vg)
meas tran vpp_vout PP v(vout)

echo "MEAS_END"
.endc

Post-Process

#!/usr/bin/env python3
import pandas as pd
import numpy as np
import yaml
import cicsim as cs
import random
import os
import string

def main(name):
  yamlfile = name + ".yaml"

  # Read result yaml file
  with open(yamlfile) as fi:
    obj = yaml.safe_load(fi)


  obj["a_input"] = obj["vpp_vg"]/obj["vpp_vin"]
  obj["a_input_dB"] = float(20*np.log10(obj["a_input"]))
  obj["a_gain"] = obj["vpp_vout"]/obj["vpp_vg"]
  obj["a_gain_dB"] = float(20*np.log10(obj["a_gain"]))

  #- use a random string to fool browser caches
  rss = ""
  if(os.environ.get("CIC_RANDOM_PLOTNAME")):
    rss = "_" + "".join(random.choice(string.ascii_uppercase+string.digits) for _ in range(5))


  fname = name + rss + "_vin_vout.png"
  print(f"Saving {fname}")
  cs.rawplot(name + ".raw","time","v(vg),v(vout)",ptype="same",fname=fname)

  # Save new yaml file
  with open(yamlfile,"w") as fo:
    yaml.dump(obj,fo)