ax = fig.add_subplot(1, 1, 1)
eee51.add_hline_text(ax, 0, 1e5, \
r'{:.1f}dB'.format(0))
ic_labels = [r'$I_C = 1mA$', r'$I_C = 10mA$']
files = [cfg['ac_sim_1mA'], cfg['ac_sim_10mA']]
for file, ic_label in zip(files, ic_labels):
freq = []
ic1 = []
with open(file, 'r') as f:
for line in f:
freq.append(float(line.split()[0]))
ic1_real = float(line.split()[1])
ic1_imag = float(line.split()[2])
ic1.append(((ic1_real**2) + (ic1_imag**2))**0.5)
index, ic1_sim = eee51.find_in_data(ic1, 1.0)
ax.semilogx(freq, 20*np.log10(ic1), '-', \
label = ic_label)
eee51.add_vline_text(ax, freq[index], 20, \
'{:.2f}MHz'.format(freq[index]/1e6))
eee51.label_plot(plt_cfg, fig, ax)
plt.savefig('bjt_2n3904_ft.png')
si_format(bjt_Is, precision=2) + r'A, $n$={:.2f}, and '.format(bjt_n) + \
r'$|V_A|$={:.2f}'.format(abs(g51.bjt_VA)))
eee51.add_vline_text(ax, reqd_vbe/g51.milli, 2.5, '$V_{BE}$ = ' + \
'{:.1f}mV'.format(reqd_vbe/g51.milli))
eee51.add_hline_text(ax, specs['ic']/g51.milli, 550, \
'$I_C$ = {:.1f}mA'.format(specs['ic']/g51.milli))
eee51.label_plot(plt_cfg, fig, ax)
# get the derivative of ic with respect to vbe
dic2 = np.diff(ic2) / np.diff(vbe)
dic_ideal = np.diff(ic_ideal) / np.diff(vbe)
index, vbe_sim = eee51.find_in_data(vbe, reqd_vbe)
gm_sim = dic2[index - 1]
gm_ideal = dic_ideal[index - 1]
# calculate the bjt small signal parameters
gm_calc = ic2[index] / (bjt_n * g51.VT)
ro_calc = abs(g51.bjt_VA) / ic2[index]
rpi_calc = bjt_beta[index] / gm_calc
ao_calc = gm_calc * ro_calc
# define the plot parameters
plt_cfg = {
'grid_linestyle': 'dotted',
'title': r'BJT 2N2222A ${\partial I_C}/{\partial V_{BE}}$',
vo_mag = np.abs(vo)
vo_phase = np.angle(vo, deg=True)
labels = ['$f_{p1}$ = ', '$f_{p2}$ = ', '$f_z$ = ']
angles = [135, 45, -45]
guess = [1e2, 1e2, 1e6, 1e9]
freq_rad = [2 * math.pi * f for f in freq]
popt, pcov = curve_fit(fmag_2p1z, freq_rad, \
20*np.log10( vo_mag ), \
p0=guess)
Ao_dB_calc = 20 * np.log10(popt[0])
index_vo0dB, vo0dB = eee51.find_in_data(20 * np.log10(vo_mag), 0)
fu = freq[index_vo0dB]
dAdf = np.diff(20 * np.log10(vo_mag)) / np.diff(np.log10(freq_rad))
# define the plot parameters
plt_cfg = {
'grid_linestyle': 'dotted',
'title': r'Common-Emitter Amplifier Frequency Response',
'xlabel': r'Frequency [Hz]',
'ylabel': r'Magnitude [dB]',
'legend_loc': 'lower left',
'add_legend': False,
'legend_title': None
}
vswp0 = float(line.split()[0])
vswp = float(line.split()[0])
if i != 0 and vswp == vswp0:
m += 1
if m == 0:
vce.append(vswp)
ic[m].append(float(line.split()[1]))
# fit the data to the ideal BJT out characteristic and find the Early Voltage (VA)
# fit the line over the linear range of the curves
# e.g. from 1V to 4V
ind1, vce1 = eee51.find_in_data(vce, 1)
ind4, vce4 = eee51.find_in_data(vce, 4)
line_m = [] # declare an array of 'slopes'
line_b = [] # declare an array of 'y-intercepts'
line_VA = [] # declare an array of 'x-intercepts' or in this case, VA
# use curve_fit to get the slopes and y-intercepts then caculate VA
for j, v in enumerate(vbe):
popt, pcov = curve_fit(eee51.line_eq, vce[ind1:ind4], ic[j][ind1:ind4])
line_m.append(popt[0])
line_b.append(popt[1])
line_VA.append(-popt[1] / popt[0])
# declare the x values for plotting the curve-fitted lines
line_x = np.linspace(math.floor(min(line_VA)), max(vce), 100)
eee51.run_spice(cfg)
# open the transfer characteristics data file and get the data
vin = [] # declare list for vin
vout = [] # declare a list for vout
ic1 = [] # declare a list for ic1
with open(cfg['transfer_data'], 'r') as f:
for line in f:
vin.append(float(line.split()[0]))
vout.append(float(line.split()[1]))
ic1.append(float(line.split()[3]))
#g51.update_bjt_VA(-15.550605626760145)
index, vin_sim = eee51.find_in_data(vin, 0.0)
vo_dc = vout[index]
# define the plot parameters
plt_cfg = {
'grid_linestyle': 'dotted',
'title': r'Common Emitter CM Bias DC Transfer Curve',
'xlabel': r'$v_{in}$ [mV]',
'ylabel': r'$v_{out}$ [V]',
'legend_loc': 'upper left',
'add_legend': True,
'legend_title': None
}
# plot the amplifier transfer characteristics
fig = plt.figure()
g51.update_bjt_vce(0.2)
# use VA from our previous analysis
g51.update_bjt_VA(-15.550605626760145)
popt, pcov = curve_fit(eee51.ideal_bjt_transfer, vbe, ic)
bjt_Is = popt[0] # yay! we get an estimate for Is and n
bjt_n = popt[1]
# generate the ic for the ideal bjt model
# using our values for Is, n, and VA at vce = 0.2V
ic_ideal = [eee51.ideal_bjt_transfer(v, bjt_Is, bjt_n) for v in vbe]
ic_ideal_mA = eee51.scale_vec(ic_ideal, g51.milli)
# get the value of vbe that will result in a 1mA ic using the simulation results
index_spec_sim, ic_spec_sim = eee51.find_in_data(ic, specs['ic'])
vbe_spec_sim = vbe[index_spec_sim]
vbe_spec_sim_mV = vbe_spec_sim/g51.milli
# get the value of vbe that will result in a 1mA ic using the our model
index_spec_ideal, ic_spec_ideal = eee51.find_in_data(ic_ideal, specs['ic'])
vbe_spec_ideal = vbe[index_spec_ideal]
vbe_spec_ideal_mV = vbe_spec_ideal/g51.milli
plt_cfg = {
'grid_linestyle' : 'dotted',
'title' : 'BJT 2N2222A Transfer Characteristics',
'xlabel' : r'$V_{BE}$ [mV]',
'ylabel' : r'$I_C$ [mA]',
'legend_loc' : 'upper left',
'add_legend' : True,
vx = []
ic1 = []
ic2 = []
itail = []
with open(dm_file, 'r') as f:
for line in f:
vid.append(float(line.split()[0]))
vop.append(float(line.split()[1]))
von.append(float(line.split()[3]))
vx.append(float(line.split()[5]))
ic1.append(float(line.split()[7]))
ic2.append(float(line.split()[9]))
itail.append(float(line.split()[11]))
index, val = eee51.find_in_data(vid, 0)
# define the plot parameters
plt_cfg = {
'grid_linestyle' : 'dotted',
'title' : r'Differential Amplifier ($V_{IC}=$' + \
'{:.1f}V)'.format(vic_value),
'xlabel' : r'$V_{id}$ [mV]',
'ylabel' : r'Voltage [V]',
'legend_loc' : 'upper right',
'add_legend' : False,
'legend_title' : None
}
# plot the amplifier transfer characteristics
fig = plt.figure()
# this was done here for convenience
eee51.run_spice(cfg)
vid = []
vo1 = []
vo2 = []
vo3 = []
with open(cfg['transfer_sim'], 'r') as f:
for line in f:
vid.append(float(line.split()[0]))
vo1.append(float(line.split()[1]))
vo2.append(float(line.split()[3]))
vo3.append(float(line.split()[5]))
index, vin_sim = eee51.find_in_data(vid, 0.0)
indexp, vin_simp = eee51.find_in_data(vid, 100e-6)
indexn, vin_simn = eee51.find_in_data(vid, -100e-6)
# define the plot parameters
plt_cfg = {
'grid_linestyle': 'dotted',
'title': r'3-Stage Op-Amp DC Transfer Curve',
'xlabel': r'$v_{id}$ [$\mu$V]',
'ylabel': r'Voltage [V]',
'legend_loc': 'lower left',
'add_legend': True,
'legend_title': None
}
fig = plt.figure()
vswp0 = float(line.split()[0])
vswp = float(line.split()[0])
if i != 0 and vswp == vswp0:
m += 1
if m == 0:
vce.append(vswp)
ic[m].append(float(line.split()[1]))
# fit the data to the ideal BJT out characteristic and find the Early Voltage (VA)
# fit the line over the linear range of the curves
# e.g. from 1V to 4V
ind1, vce1 = eee51.find_in_data(vce, 1)
ind4, vce4 = eee51.find_in_data(vce, 4)
line_m = [] # declare an array of 'slopes'
line_b = [] # declare an array of 'y-intercepts'
line_VA = [] # declare an array of 'x-intercepts' or in this case, VA
# use curve_fit to get the slopes and y-intercepts then caculate VA
for j, v in enumerate(vbe):
popt, pcov = curve_fit(eee51.line_eq, vce[ind1:ind4], ic[j][ind1:ind4])
line_m.append(popt[0])
line_b.append(popt[1])
line_VA.append(-popt[1] / popt[0])
# declare the x values for plotting the curve-fitted lines
line_x = np.linspace(math.floor(min(line_VA)), max(vce), 100)
return H, H_mag, H_phase
T, T_mag, T_phase = TransferFunction(ifb, ierr)
Rm, Rm_mag, Rm_phase = TransferFunction(vo1, ierr)
F, F_mag, F_phase = TransferFunction(ifb, vo1)
Finv, Finv_mag, Finv_phase = TransferFunction(vo1, ifb)
Rcl, Rcl_mag, Rcl_pgase = TransferFunction(vo3, iin3)
popt, pcov = curve_fit(fmag_2p1z, freq_rad, \
20*np.log10( T_mag ), \
p0=guess)
To_dB_calc = 20 * np.log10(popt[0])
index_To0dB, To0dB = eee51.find_in_data(20 * np.log10(T_mag), 0)
fu = freq[index_To0dB]
dTdf = np.diff(20 * np.log10(T_mag)) / np.diff(np.log10(freq_rad))
PM = T_phase[index_To0dB] - (-180)
# define the plot parameters
plt_cfg = {
'grid_linestyle': 'dotted',
'title': r'Shunt Amplifier Loop Gain (PM = {:.1f} deg)'.format(PM),
'xlabel': r'Frequency [Hz]',
'ylabel': r'Magnitude [dB]',
'legend_loc': 'upper right',
'add_legend': True,
'legend_title': None