Republic of the Philippines Mindanao State University - Iligan Institute of Technology
College of Engineering Engineering Tibanga, 92 Iligan !ity, P"#" $o% &o"'()) Tel" &os" *(+ 22-)' .oc"+ /irect line *(+ 2+'0-1ailfbalagao3yahoo" 2+'0-1ailfbalagao3yahoo"co1 co1 4o1epage http55666"1suiit"edu"ph5coe
Department of Electrical, Electronics and Computer Engineering
LABORATORY REPORT on Activity No. 2
Common Source Amplifer with Reitive Lo!" !n" Source #e$ener!tion In partial fulllment for the course ECE 126 (Introduction to Analog IC Design)
Su%mitte" %y& T!ED, "ohn #a$ier %&
Su%mitte" to& %rof& Allenn C& !o'aton ctoer 21*
PROCE#'RES a& +ollo'ing the circuit in gure &1, simulate the
V ¿ −V out
DC transfer cur$e
as it 'as otained in gure &2 and the fre-uenc. response as in gure &/&
V ¿−dc =0.4 V
V ¿−dc =0.87
V ¿−dc =1.52
(i$ure ).!. DC Anal.sis of the Common 0ource Amplier 'ith esisti$e !oad and Aspect atio &63&14 This graph sho's the DC gain cur$e of the conguration such that the output $oltage can e otained using the $alues of input $oltage at the hori5ontal ais of the graph
V ¿( dc) =0.4 V ; V out ( dc )=1.8 V V ¿( dc) =0.87 V ;V out ( dc )=1.0 V
V ¿( dc) =1.52 V ; V out (dc ) =0.2 V
(i$ure ).%. AC Anal.sis of the Common 0ource Amplier 'ith esisti$e !oad and Aspect atio &63&14 for di7erent $alues of 8in&
This graph sho's the AC anal.ses of the same conguration 'ith di7erent $alues of 8in(dc) gi$en . the test point at the DC gain cur$e ao$e& It means that a higher DC gain can e otain at the point of in9ection of the DC gain cur$e& & Change the $alue of in gure &1 and simulate the follo'ing 'a$eforms of gure &, then list the results as tale &1 and compare them 'ith hand calculations results&
V ¿( dc) =0.7 V ;R =10 kΩ V ¿( dc) =0.9 V ; R =5 kΩ V ¿( dc) =0.5 V ; R =20 kΩ
(i$ure 2.!. AC Anal.sis of the Common 0ource Amplier 'ith esisti$e !oad and Aspect atio &63&14 +or di7erent $alues of 8in and d&
Common Source Amplifer with Reitive Lo!" Rs
V ¿( dc)
A*"B+
,"B*-+
/0
1. 3
,.)
/.// 4-
)10
1.5 3
5.6)
,.5/ 4-
210
1./ 3
,.6/
)./5 4-
T!%le ). Data :athered for Common 0ource Amplier 'ith esisti$e !oad& ser$ing the graph ao$e, the conguration 'as anal.5ed . $ar.ing the input DC $oltage and the $alue of the load resistor or d& After each $ariation of the parameters, the graph 'as anal.5ed . locating certain points at the stale maimum $oltage gain and at the ;/d< point of the AC cur$e&
c& +ollo'ing the circuit of gure &*, simulate
V ¿ −V out
DC transfer cur$e as in
gure &6 and the fre-uenc. response as in gure &=&
V ¿−dc =0.53 V
V ¿−dc =0.88 V
V ¿−dc =1.26 V
(i$ure ,.!. DC Anal.sis or the DC gain cur$e of the Common 0ource Amplier 'ith 0ource Degeneration and Aspect atio &63&14&
−3 dB point
(i$ure ,.%. AC Anal.sis of the Common 0ource Amplier 'ith 0ource Degeneration and Aspect atio &63&14& At gure /&a, the DC gain cur$e of the Common 0ource Amplier 'ith 0ource Degeneration 'as otained and otaining certain points of concern& At gure /&, the AC gain cur$e 'as otained and also locating the ;/d< point
of the cur$e 'hich is the critical point in a ode plot or fre-uenc. spectrum anal.sis& This point 'ill pinpoint the and'idth fre-uenc. of the graph&
d& Change the $alue of
Rs
in gure &* and simulate the resulting 'a$eforms
of gure &4> list the results as in tale &2& Then, compare them 'ith the hand calculation results&
(i$ure 7.!. AC Anal.sis of the Common 0ource Amplier 'ith 0ource Degeneration and Aspect atio &63&14 for di7erent $alues of s&
Common Source Amplifer with Source #e$ener!tion Rs
V ¿
A ( dB )
8,"B *-+
)09
1.: 3
6.1/
7.7: 4-
209
1. 3
7.7:
,.62 4-
,09
).1 3
,.16
2.6 4-
T!%le 2. Data :athered on di7erent $alues of s& At gure &a, it otained three AC cur$es for each ha$ing di7erent $alues of s and 8in& <. pinpointing the $oltage gain and ;/d< point of each graph, the and'idth fre-uencies of the cur$es are otained&
e& Change the $alue of
Rs
in gure &* and simulate the 'a$eforms of gure
&1 to oser$e the relationship et'een
I ds
and
V ¿
&
Rs =0 Ω Rs =0 .5 k Ω Rs =1 k Ω R s =1.5 k Ω
(i$ure /.!.
I ds−V ¿
characteristic cur$e 'ith di7erent $alues of s 'ith aspect
ratio of &63&14& The graph sho's the relationship et'een Ids and 8in& <. oser$ing the graph ao$e, it sho's that increasing the $alue of source resistance 'ill lead to the decrease of the $alue of drain current signicantl.& f&
+ollo'ing the amplier conguration of gure &11, the input signal is an ideal sinusoidal 'a$e 'ith &*8 amplitude, and the fre-uenc. is 1?@5& %erform the ++T anal.sis to V ¿ to get the fre-uenc. spectrum li?e gure &12&
;2&
;4& d<
;4&1
;4*&1
;11&
;11/&
;11&
(i$ure 6.!. ++T anal.sis of 0ource Degeneration 'ith s *B& g& %erform the ++T anal.sis to the $alue of
Rs
V out
in the circuit of gure &11 'hile changing
to get the fre-uenc. spectrum li?e gure &1/;16& !ist the
results of gure &1/;16 li?e tale &/&
(i$ure 5.!. ++T anal.sis of 0ource Degeneration 'ith s *B&
(i$ure 5.%. ++T anal.sis of 0ource Degeneration 'ith s 1?B&
(i$ure 5.c. ++T anal.sis of 0ource Degeneration 'ith s 1&*?B&
;'EST
g m R D 1
+ g mR
S
It is clear that increasing the gain of a C0 amplier 'ould mean an increase the $alue of d& If 'e increase the $alue of d it 'ill also ma?e it more linear and ha$e fe'er occurrences in the saturation region& & eplace
Rs
in gure &11 . a diode;connected 0& Fsing the steps 'e
follo'ed efore, 'hat is the DC gain of this circuit
A6&*
A&/6
A;/&=*
<. changing the s 'ith a diode;connected 0, the DC gain cur$e is impro$ed& It means that the output $oltage is increased compared to the output $oltage in t.pical source resistor relati$e to the same input $oltage for oth&
c& Fsing the conguration of -uestion 2, perform the ++T anal.sis of V out
V ¿
and
to get the fre-uenc. spectrum of the 'a$es& Ghat happens to this
circuit linearit. Is there an. di7erence 'ith gure &11&
ser$ing the graph, the second and the third harmonics of the graph is e-ual to ;41& d< and ;4&/ d<& 0ince the t'o $alues are approimatel. close to each other, it means that the circuit linearit. is good compare to the graph of gure & 11 in 'hich the second and third harmonics are distant to each other&
