Summary Handwritten notes of ES2C0 Analogue Electronic Design

Analogue Electrical Design
Basics R R-
-


the toner Diode
R ,"
-
-
.

R ,
= REV
R' R2
Potential Ven
t
Dividers
Designed for the operation the
°

in reverse -
brakedown
y
✓out Rr Zener diode has bracedown voltage
region
=
r. a
•




R, Rz Extrinsic Silicon
.



+ •
-
Add
to the
equal output Voltage -




to make
PI Rz impurities a

↳
R =
2- Rz
A material semi
conducting
-



run
Cathode
&
type type
t
n
p
- -



vz Brauedown


7¥
-




°


NO movement " "age h h

of charge These materials have
mostly
Vo Load


hole (positive ) VD

through carriers or
.




a
ph junction at
-




cnegan.ve ,
an.ae
demon came,
voyage , cons,.am,

equi,;w,um ,




region Region


Biasing
pn junction
a - : known as a diode ; The current cannot
barrier
Amplifier Modelling
flow from p to n unless the inbuilt
potential
external circuit
is overcome
by the .
-
- - - -
- - -
. . -
. .
,
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y


Ubi
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O H
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A l l


Output Vs
'
Rin
±
Axvin
'
Toad
Input ' l
Pot
gal '

Output Axinput
.

i
vin
Thermal Voltage
, - -
-
,
,



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'

. -
÷

kIq
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-




VT
-
-



Room
-




25mV Temp
- - - -
-



at
- - -
-
-

=




Vent
Voltage Gain Av
•

, : -

-




Vin
•
Reverse Brake down Reverse voltage : to reach °
Power Gain :
Ap -
-




a certain value , avalanches and makes
•
Current Gain :
A;

huge current .



Only limited
by external circuit .




Feedback V
E ous
A
t
7 ,




Forward Bias
i .Vin
DC
:
voltage positive terminal connected
Negative Feedback System
.




B s
to the and Gets
p region negative to the n
region
to
vous
-
-
t

Vo Alvin sprout )
.




E A 7 ,
-
-
-




O FV and then Vin
around current
flows
-

-




#p
.




=

s s
Diode Characteristic TV curve . n

anode cathode
im f
-
-
Feedback Fraction •

Positive Feedback leads to




)
+

(Vin flout ) A
-




Reverse saturation VD Vo -
-
-

oscillation
current
Is =
Reverse Saturation Current

¥ ,¥p
b
loop Vt = Thermal voltage =
Eat:{Id -
- Acn
"T
, " .




(
"" ^
"
Wh " ✓ " ° '
" "
"
"



Oscillators
iii. Is
(÷) a) -




With positive feedback P will
R
.
frequency be a


selective network at low
frequencies only need
Vss Rip
-


-

-
+ Vp
Aeuljwl VI z.f-p-g.co,
+

capacitive circuits
Qa
-




(
-




1) TV
-
-




Vd
.
.




Vss -



vs, = RI, e
-


,
•
Sinusoidal Oscillators -


The Barkerhauser Criterion
The diodes have to have a resistor to limit the current or it
)
Loopgain LGW AB Gw) At
-
-
-




the
destroy itself
•




phase loop
-




will . wo

loop gain
'




% must be zero
At specific frequency
•

a

Plot Either the TD
-
-
O
VFR and the
magnitude of
loop gain (Ap )
the load lines
°

diode
'
→
to the
behaves like aractaistic loop gain must be
unity
a short circuit or an ACL will tend to
infinity "
open circuit .
.


If it behave, as a
conman ya , .nu," .am sustain man"IEp%7%:::
short circuit the current is ¥ Exide
oscillations of
no input
applied '




•

If it behaves as circuit
frequency w
°
To sustain oscillation AB
-

I
an
open vans -


,
in O

Apljw) I
-




)
Lcjw
-




will not be sinusoidal
two is = =
current AB >1 oscillations
no
flows .




Apc 1 oscillations will die out .




°

Diode not
conducting and not
forward biased
The
=
'




frequency of oscillation Wo is determined
Soley by the phase
effectively open circuit
only reverse currentflows .




characteristics of the feedback loop .
The loop oscillates at the


Diode frequency which the phase is zero
conducting
°


is it conducts
assume
perfectly
.




V silicon 20.7
-
-



.