# Chapter 4: Linear Power Amplifier Integrated Circuits¶

### Example 4.1,Page 162¶

In [1]:
#finding voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Rf=1;
Ri=10;
Vi=0;
Ip=500;

#calculation
Vrf=Ip*Rf;

#result
print "output voltage is",round(Vrf,2), "mV"

output voltage is 500.0 mV


### Example 4.2,Page 165¶

In [2]:
#finding frequency

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Vi=300.0;
P=35.0;
R=8.0;
S=10000.0;
fh=20.0;

#calculation
Vl=(P*R)**.5;
Vp=Vl*2**.5;
Il=Vl/R;
f=S/(2*pi*Vp);
Ao=Vl/Vi;
G=Ao*fh;

#result
print "frequency of OPA548 is",round(f,2), "KHz"
print "slew rate of OPA548 is",round(G,2), "Mhz"
print('the OPA548 can be used')

frequency of OPA548 is 67.26 KHz
slew rate of OPA548 is 1.12 Mhz
the OPA548 can be used


### Example 4.3,Page 168¶

In [3]:
#finding power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Rl=10.0;
V=12.0;
Vl=5.0;

#calculation
Pl=Vl**2/Rl;
I=Vl/Rl;
Ps=V*I;
Pic=Ps-Pl;

#result
print "power delivered is",round(Pic,2), "watt"

power delivered is 3.5 watt


### Example 4.4,Page 170¶

In [1]:
#finding Vload vs Pic graph

#initialisation of variable
%matplotlib inline
import numpy as np
import matplotlib.pyplot as plt
Vload=[0.0, 0.2, 0.4, 0.6, 0.8, 4.8, 5.0, 5.2, 5.4, 5.6, 5.8, 6.0, 6.2, 6.4, 11.4, 11.6, 11.8, 12.0];
Iload=[0.0, 0.0, 0.0, 0.1, 0.1, 0.5, 0.5, 0.5, 0.5, 0.6, 0.6, 0.6, 0.6, 0.6, 1.1, 1.2, 1.2, 1.2];
Pload=[0.00, 0.00, 0.02, 0.04, 0.06, 2.30, 2.50, 2.70, 2.92, 3.14, 3.36, 3.60, 3.84, 4.10, 13.00, 13.46, 13.92, 14.40];
Ps=[0.00, 0.24, 0.48, 0.72, 0.96, 5.76, 6.00, 6.24, 6.48, 6.72, 6.96, 7.20, 7.44, 7.68, 13.68, 13.92, 14.16, 14.40];
Pic=[0.00, 0.24, 0.46, 0.68, 0.90, 3.46, 3.50, 3.54, 3.56, 3.58, 3.60, 3.60, 3.60, 3.58, 0.68, 0.46, 0.24, 0.00];

#result
for i in range(0,18):

plt.ylabel('IC Power(W)')
plt.show()

Vload     Iload     Pload          Ps        Pic
0.0       0.0        0.0          0.0        0.0
0.2       0.0        0.0          0.24        0.24
0.4       0.0        0.02          0.48        0.46
0.6       0.1        0.04          0.72        0.68
0.8       0.1        0.06          0.96        0.9
4.8       0.5        2.3          5.76        3.46
5.0       0.5        2.5          6.0        3.5
5.2       0.5        2.7          6.24        3.54
5.4       0.5        2.92          6.48        3.56
5.6       0.6        3.14          6.72        3.58
5.8       0.6        3.36          6.96        3.6
6.0       0.6        3.6          7.2        3.6
6.2       0.6        3.84          7.44        3.6
6.4       0.6        4.1          7.68        3.58
11.4       1.1        13.0          13.68        0.68
11.6       1.2        13.46          13.92        0.46
11.8       1.2        13.92          14.16        0.24
12.0       1.2        14.4          14.4        0.0


### Example 4.5,Page 173¶

In [4]:
#finding different power and current

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=12.0;
Vp=5.0;
R=10.0;

#calculation
Ip=Vp/R;
Il=Ip/2**.5;
Pl=(Vp*Ip)/2;
Id=Ip/pi;
Pt=2*V*Ip/pi;
Pic=Pt-Pl;

#result
print "IC power is",round(Pic,2), "W"
print "total power is",round(Pt,2), "W"
print "dc supply current is",round(Id*1000,3), "mA"
print "power delivered is",round(Pl,2), "watt"

IC power is 2.57 W
total power is 3.82 W
dc supply current is 159.155 mA
power delivered is 1.25 watt


### Example 4.6,Page 179¶

In [5]:
#finding thermal resistance

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Ts=40.0;
P=2.92;
Qj=2.5;
Qc=2.0;
Tj=125.0;

#calculation
Qs=(Tj-Ts)/P-Qj-Qc;

#result
print "thermal resistance is",round(Qs,2),"C/W"

thermal resistance is 24.61 C/W


### Example 4.7,Page 180¶

In [48]:
#finding power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
V=24.0;
R=10.0;
Qs=4.0;
Tj=125.0;
Ta=40.0;
Qj=2.5;
Qc=2.0;
Ps=[14.36, 14.67];
Pic=[9.94, 10.06];

#calculation
P=(Tj-Ta)/(Qj+Qc+Qs);

#result
for i in range(0,2):
print round(P,2),"power delivered by IC in watt"

Vload     Iload     Pload         Ps        Pic
9.4       0.94        4.42       14.36        9.94
9.6       0.96        4.61       14.67        10.06
10.0 power delivered by IC in watt


### Example 4.8,Page 182¶

In [7]:
#finding current and voltage

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan
Rf=22.0;
Ri=1.0;
Rs=15.0;
I=4.75;
Rc=4.0;
Vp=2.0;
Rl=8.0;
Im=4.0;

#calculation
Av=1+(Rf/Ri);
Il=(Rs*I)/(Rc+13.75);
Vo=Vp*Av;
V=Im*Rl;

#result
print "gain is",round(Av,2)
print "limit current is",round(Il,2), "A"
print "output voltage is",round(Vo,2), "V"
print "maximum output voltage is",round(V,2), "V"

gain is 23.0
limit current is 4.01 A
output voltage is 46.0 V
maximum output voltage is 32.0 V


### Example 4.9,Page 185¶

In [8]:
#finding loudness

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
D=8.0;
d=1.0;
I=90.0;

#calculation
Is=20*log(d/D,10);
Ir=I-Is;

#result
print "loudness ofsound is",round(Ir,2), "dB"

loudness ofsound is 108.06 dB


### Example 4.10,Page 186¶

In [14]:
#finding power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
D=1.0;
I1=108.0;
I2=95.0;
P=1.0;

#calculation
I=I1-I2;
Pr=P*10**(I/10);

#result
print "power provided is",round(Pr,2), "watt"

19.95 power provided in watt


### Example 4.11,Page 188¶

In [9]:
#finding output voltage and gain

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
P=20;
R=8;
Vi=1.23;

#calculation
V=(P*R)**.5;
G=V/Vi;

#result
print "output voltage is",round(V,2), "V"
print "gain is",round(G,2)

output voltage is 12.65 V
gain is 10.28


### Example 4.12,Page 191¶

In [10]:
#finding resistor and capacitor

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
G=40.0;
f=80.0;
R1=15000.0;
R2=150.0;

#calculation
R=2*(R1/G)-R2;
R11=620;
C=1/(2*pi*f*R11/7);

#result
print "resistor b/w pins 1&8 is",round(R,2),"ohm"
print('thus pick a 620 ohm resistor')
print "capacitor b/w pins 1&8 is",round(C*1e6,2), "microF"
print('thus pick a 27 microF capacitor')

resistor b/w pins 1&8 is 600.0 ohm
thus pick a 620 ohm resistor
capacitor b/w pins 1&8 is 22.46 microF
thus pick a 27 microF capacitor


### Example 4.13,Page 193¶

In [11]:
#finding thermal resistance and power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
R=8.0#resistance
V=5.0#voltage
Tm=150.0#temperature
Ta=50.0#temperature
Qa=107.0;
Qc=37.0;
Ps=299.0;

#calculation
Vd=V/2;
Vm=V-1;
Vp=Vm-Vd;
Vr=Vp/2**.5;
Pl=1000*Vr**2/R;
Pl=140;
Pic=Ps-Pl;
Q=(Tm-Ta)/Pic;

#result
print "power dissipated is",round(Pl,2), "mW"
print "thermal resistance is",round(Q*1000,2),"degree C/W"

power dissipated is 140.0 mW
thermal resistance is 628.93 degree C/W


### Example 4.14,Page 197¶

In [12]:
#finding power delivered

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
R=8.0#resistance
V=5.0#voltage

#calculation
Vl=V-1;
Vp=Vl-1;
Vr=Vp/2**.5;
P=Vr**2/R;

#result
print "power deliverd is",round(P*1000,2), "mwatt"

power deliverd is 562.5 mwatt


### Example 4.15,Page 201¶

In [13]:
#finding thermal resistance and power

#initialisation of variable
from math import pi,tan,sqrt,sin,cos,acos,atan,log
R=8.0#resistance
Ts=35.0#temperature
Ta=150.0#temperature
Vm=42.0#voltage

#calcuation
Vp=Vm-5;
Vr=Vp/2**.5;
Pm=Vr**2/R;
P=45;
Qs=(Ta-Ts)/P-1.2;

#result
print "power delivered is",round(Pm,2), "watt"
print "thermal resistance is",round(round(Qs*10)/10,2), "degreeC/W"

power delivered is 85.56 watt
thermal resistance is 1.4 degreeC/W