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Page 1: Basic FET Amplifiers

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Page 13: Basic FET Amplifiers

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Page 14: Basic FET Amplifiers

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Page 16: Basic FET Amplifiers

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Page 17: Basic FET Amplifiers

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Page 18: Basic FET Amplifiers

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Page 20: Basic FET Amplifiers

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Page 21: Basic FET Amplifiers

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Page 22: Basic FET Amplifiers

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Page 35: Basic FET Amplifiers

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vGSD

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" $ &! ! !

/"++ * !

!" %

!"

+

vDS

iD

vDSvDD

iD

iD(max)

vDS (sat) = – VTNLvGS = 0

Slope = 1rO

Transitionpoint

(a) (b)

$&! /( %& $ %'& 0

Page 39: Basic FET Amplifiers

* /

Q-point

vO

vGSD

I IIII III IV

C

B

A

VTND0

VDD – VTNL

VDD

(c)

$&! /' %& $ 1 %'& 1 %&

+

vDSL

VDD

iD

vO

+

vDSDMD

vi

+

–VGSDQ

+–

ML

vDSD

VGSDQ

VDD

iD

iD(max)

Q-pointLoad curve

B C

A

(a) (b)

$&! //

Page 40: Basic FET Amplifiers

, -!

$ !

,

*

!

"

)"! ( *+!%,!- - $ ! 1

"

/"+.34

756 * 0:6 062 * 7262

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2072

759+6

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0

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756 * 026 2:762 * 2: 62 * 77060 :6" 34 - $

" 34 * & " 34 - $

! " 3" 34 0056B 34 .8B 34 , 2:84

Page 41: Basic FET Amplifiers

2' 9 "8! ;%

$ $ ! $

! /"+:34 $

" $ ! /2 /.

"

:".9 * :" % $ $

* "

! /2 /"+:34" $

$ ! /." !

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, - $"

% $ &! $

! " % 2 &! '

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$&! /1 %& ! $1 %'& ) %& %&

Page 42: Basic FET Amplifiers

, -!

/2 # " $ &! !

! /"+/" $

$ !" %

/0 /0

/2 /2"

< "

$ !

,

$ !

"

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+762 )* 0:)* .7 77060" 72"

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2

0

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)

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0:72

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0

0

77072 :77 '

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, 7/9.:77:77 08.

.""!%- ! *

1 " <! *

"

$&! / ! $

Page 43: Basic FET Amplifiers

* /

:&- /"+:34

! /0 ! GGHH $" %

$

$ " <!

* $ "

* *

$ $ " /"+834 34

"

% $ ! /2 $

$ !" /0

/0" $

! /2 $ !"

/0 /0"

% $ $

' "

/0 !

! " %

"

5 4

$ ! " ( & ! ( $ "

$&! /2 %& ! $1 %'& ! $

Page 44: Basic FET Amplifiers

, -!

/"+5" ! $

! ! ! ! 0

! " ! !

! " E

' "

B (

&"

5 :.

/"+9 $

$ " ! $

! $ ! $

"

+

–vi

Ri1 Ro1 Ri2 Ro2

AV1

+

–vo

Stage 1

AV2AV1

Stage 2

$&! /5 34 $

+– R2

vi

R1

CC

CS

RD1

RS1 RS2

M1

vo

RL =4 kΩ

CC2

V + = 5 V

V – = –5 V

M2

Ri

RSiRo

$&! /6 ! $

Page 45: Basic FET Amplifiers

* /

:!$ )"! / *+!%,!- -

&"* /"+9

0 :77 62 2 277 62 0 2 026 0 2 7" -

0 72 2 7: 0 2 /6 077 '" E + '

&%- /2 !

2 : : 22

/ 07 7:2

2 5 '"

2 22 22

7: 722 022

2 2856

2 /6 ! /2 2 06" % 2 2856 ! /2

2 0 285 0856

0

0 : 085

72 0/0 '

0 /6 ! /0

0 085 / +226

0

0 +22 :

72 .9 '

/0 !

0 00 02

72 7:70 022

0 05.6

0 2

0 2

0 2

07 00

Page 46: Basic FET Amplifiers

, -!

/":7 $ "

/0 /2

$ " !

& "

2

0 2

0

0

02

0 2

0

0

05. 0

0

07707 72.9

0 .5. '" 077 ' 2 0.: '"

.""!%-

"

R3vi

CC

R2

R1

CG

CS

RD

V + = 5 V

V – = –5 V

vO

RS

+–

M1

M2

$&! 1

:!$ )"! 1 *+!%,!- -

&"

/":7 ? 0 2 026 0 2 7562 0 2 7" E 0 2 . .77 '

07 '" - 7+

0 2 2:6"

&%- ! /0

0 : 7+07 : 06

Page 47: Basic FET Amplifiers

* /

/0 /2 ( $$ ! !" % !

2

7+ 75 022

0906

0 .

0 2 .

: 0

.

.77

: 090 0 790

. :+/ '

! /2

2 2 2 2: 0 0:6

2 2 .

0 2 .

: 2

2 .

.77

: 090 0: .+06

2 . 27+/ '

2 0:7 '

0 9:+ '

! /2

2 2 2 2: 0: +6

: 2

: +

7+ 2: '

.""!%- 2:6 090 02 7806

"

Page 48: Basic FET Amplifiers

, -!

5( "#$

$ ! ( $ &! "

)"! *+!%,!- - $ ! "

* /"+9

! ( /"0+"

&%- $

0 2 00 0 27:705. 02 7/.6

2 2 22 2 272285 02 7/.26

$ &! /":0"

!

222*

2 000

0

2 00

2 00

2*

$ !

Vgs1

Vo

gm1Vgs1

Vgs2

–+

+

gm2Vgs2

Vi RD1 RL

Ri

RSi

+– R1R2 RS2

$&! 1

Page 49: Basic FET Amplifiers

* /

,

02#02*0 22*

, 7/.7/.20/05+

0 7/.25+ 077

077 +

/0.

.""!%- $ ! $

0 ! $ "

! $ $

"

)"! 2 *+!%,!- - $ ! "

/":7

! ( /"0:" ! "

&%- $ $

&"

0 2 2 275090 02 00+6

$ &! /":2" /0 /2 0" /2 $ " !

00

0 $ !

,

0

, 00+2: 25:

.""!%- $ !

$ " $

& "

Vgs1

Vo

gm1Vgs1

+

gm2Vgs2 = gm1Vgs1

Vi RD+– R3R2

$&! 1(

Page 50: Basic FET Amplifiers

, -!

!% 3& 4 !% $

# /"+9 $ ! ( /"0:" * $ " 3$ &! /"0:"4 3" 0.2 '4

() ! /"+9

076 076" ? 0 2 0620 2 26 0 2 77060" 34 E * + ' 0 2 2 0 2 076 277 '" 34 *

$ ! " 3" 34 2 : '0 .. ' 0 080 ' 0 :5/ ' 2 .7+ 'B 34 , 57/ 7..7 '4

) $ ! /":7 076 076" ? 0 2 0262

0 2 26 0 2 7" 34 E 0 2 . :77 ' 07 '"- 0 0 2 .:6" 34 - $ ! " 3" 34 . 0+:: ' 2 08: ' 0 089: '

. 'B 34 , /:84

6 7. <

E' ) $! " ! $ &! )" % ) "

6 "#$ 0&,!% .&%

/":. ) $! " $$ !

$ $$ ! "

0

.

2

. ! " & 3/":.4 3/":+4

0

.

.

2

( & !

0

.

2

2 0

.

.

.

2

& 3/":/4 & $!

VDD

iD

iG

vO

+

vi

+

–VGS

+–

RD

vDS

+

–vGS

$&! 1' 5*

Page 51: Basic FET Amplifiers

* /

! & ! " " ?

.

2 0

.

& 3/":84 $ ) "

1 2 & 3/":/4

# $!

# 2

.0

.

$ $ $$ ! " %

#

2

.0

.

. ! $ ) !" $ $ )

2

.0

.

%

$$ "

' !$ # $ " & 3/":+4 ( ' ) " &

0

.

2

0

$

0

= & 3/"/+4

Page 52: Basic FET Amplifiers

, -!

0

.

2 0

0 0

$ &! $ ) /":+ ( $ " $ &! $ ) $ " <! $$! ! $ !"

6( "#$

$ &! ) $ " ) "

)"! 5 *+!%,!- - $ ! ) $ "

* /":: 02. +6 777560" - $ ! , "

&%- & $$ !

2

0 2

Vgs gmVgs ro

+

G D

S

$&! 1/ 5*

vi

CC1

CS

vo

RL = 4 kΩ

R2 = 180 kΩ RS = 2.7 kΩ

R1 = 420 kΩRD = 2.7 kΩ

CC2

VDD = 20 V

+–

$&! 11 ! 5* '

Page 53: Basic FET Amplifiers

* /

0

.

2

* &

057

057 +27

27 0228 0

+ 2

272:2 082 2/+ 7

2706

&

0

.

2

02 0 270+

2

298

$

2

.0

.

202

+ 0 270+

2956

0

0

7775298 +20 '

$ &! /":/"

$ !

,

*

, 295+2028+ +/2

.""!%- ! )

"

Vgs

Vo

gmVgs ro

+

RLVi RDR1R2+–

$&! 1 5* '

Page 54: Basic FET Amplifiers

, -!

:!$ )"! 6 *+!%,!- - ) $

$ ! "

$ /":8 ?

02 . +6 77060" -

$ ! , 797"

&%- $ &! /":5"

!

*

!

* $ !

,

*0 *

( "

vi

CC1

vo

RL = 10 kΩRG = 50 kΩ

+10 V

–10 V

RS

CC2

+–

$&! 12 5*

Vgs

gmVgs ro

–+

RS RLVi

Vo

RG+–

$&! 15 5*

Page 55: Basic FET Amplifiers

* /

( !

" (

( " $ ! $

! ! "

!% 3& 4 !% $

% @ ) /"::

! ( /"09" - $ ! 27 '

" 3" , .95) & ) /":: ?

+ . .6 777:60" E * + ' 28 '

0 2 :77 '" @ 02 026"

* $ ! " 3" .98 ' 0 +:. '

2 +8 ' , 2584

(!' /":9 ?

/ . 26 7" 34 * &

2

.0

.

202

+0

+

' ! 2;6 2/86

&

0

.

2

02 0 2/8+

2

0..

!

07

2/8 07

0.. 9:. '

!

0

0

7700.. 8:2 '

$ !

, *

0 * 29:.078:2

0 29:.078:2 7972

.""!%-

&"

Page 56: Basic FET Amplifiers

, -!

$$ ! " 34 - ! $ !

, " 3" 34 0 0 0 026 2 028 2 0+96B34 , 27:4

! @ $ /":8

5 . .:6 77060" 34 -

2" 34 * $ ! * "

34 - ! * $ 27

! 34" 3" 34 :55 ' 34 , 792. * 0/+ '4

4 3

" $ &! !

"

? $

" '

( " $ !

"

/"0"

!

! 3*4 ! "

( (

("

$ &! ) !

! ) "

..=9

! ?

( "

3 /"04

- $ &!

! $ " 3 /"04

+–

vi

CSQ1

vo

RL = 2 kΩ

R2 = 430 kΩ

R1 = 70 kΩ RS1 = 4 kΩ

RS2 = 4 kΩRD1 = 4 kΩ

CC2

CC1

VDD = 20 V

Q2

$&! 16 ( .,

Page 57: Basic FET Amplifiers

* /

$ &! !

$! "

* $ ! $

" 3 /".4

* $ ! $

" 3 /"+4

* $ ! $

" 3 /":4

- 1

, " 3 /"84

$ &!

" 3 /"54

- ) " 3 /"94

>49

0" - $

$ $! "

2" < $$ $ !

$ A

." - $ "

+" < $ &!

A

:" ' $

3! 4"

/" - $

"

8" % ! $ $

$ A

5" % $

A

9" ' $

3! 4"

07" - $

"

00" ' $

3! 4"

02" - $

"

0." * $ $

$ "

0+" !

"

0:" &

$ "

0/" I! ) !

"

Page 58: Basic FET Amplifiers

, -!

7

!% ! "8!

1 756 0 +7 62 7" 34

- $$ )* 7:;6 7:

" 34 * & ! "

( , . 026 0 276 7" 34

- $$ )* :7 6 70 " 34 * & ! "

' 1 "

. :6 .+ 076" - "

/ ! $ ,

077 '" 770260 ( ! "

1 * $ ! /"0 0;6 :7 ' 07 '"

?: /"0 ?

756 770:60 0 /7 62" E 076" 34 - $

$$ )* 7: /6" 34 * " 34 % $ ! , A

?2 $ ! & 3/"+4"1 & 3/".4 " & 2 & ! + " ( ( " J<? = $ 2 0

2 02 2"K

5 = , /"8 ' $ 0 .6 06"

!% ' .""#&! "8!

6 * $ ! $ /"0. 0;6 :7 ' 07 '"

2 ' 02 :7 '"

$ /"0. ( $ 077 ' : '" - $ ! , 07" 7"

1 $ ,/"00 $

? 26 062 7" ? 026 2 ' . ' 0 .77 ' 2 277 '" 2 ' * . ' ! "

34 - & ! " 34 $ ! " 34 - ( ! "

( ,/"00 0:6 2 ' * : ' 7: ' 277 '" 34 0 2 . 26

262 7" 34 - $ ! "

' @ , /"00 '"

Page 59: Basic FET Amplifiers

* /

?/ $ ,/"0+ 06 7:62 77060" ? :6

:6 * 07 '" 34 - ! ( $ ! " 34 $ ! "

:1 $ ,/"0: ? 06 +62 7" 076

* 2 '" 34 - 2 /6" 34- $ ! " 34 (! !"

? $ ,/"0: $ ! , /"0:" :6

* 2 '" 34 2:6" 34 - $ ! "

?2 * , $ ,/"08 . 26 7 * 07 '" 34

- ! /6" 34 - ! $ ! " 34 * !

+– R2

vi

Rin R1

CC1

CC2RD

VDD

vo

RS

RL

$&!

VDD

vi

vo

RG = 1 MΩ+–

RL

RS

RD

CC1

CC2

$&! 1

V +

V –

vi

vo

RG =200 kΩ

+–

RL

IQ

RD

CC1

CC2

CS

$&! /

Page 60: Basic FET Amplifiers

, -!

34 ! ! & 34A

:5 $ ,/"08 , $ ? . 0:6 :62 7" * 2 '"34 - 0 :6" 34 - $ ! , " 34 % (

! A

?:6 - $ ,/"09 $ 7" & ! / 256 076" 22;6" E * 0 ' , 0 077 '" 02 "

?( $ ,/"27 ? . 0:6 262 77060" !

* 27 '" 70*" 34 - $ " 34 - $ * $ !

" 34 $ ! *

A

vivoRG =

100 kΩ+–

RLRD

RS

CC1

CC2

+5 V

–5 V

CS

$&! 2

+– R2

vi

Rin R1

CC1

RD

VDD = 18 V

vo

RS

RL

CC2

$&! 6

vivo

RG = 500 kΩ+–

RLRD

IQ

CC1

CC2

+9 V

–9 V

CS

$&! (

Page 61: Basic FET Amplifiers

* /

:( ,/"20 ? . 26 7:62 7" 34 - 2 /6" 34 - $ ! , "

?:(( - $ ,/"22 ! $ ! , 07 * 27 ' 277 '" $ 0 076" E

26 7"

!% / &!#;! "8!

(' $ $ +6 :7 '" - $ ! " *

$ ! 2: ' "

(/ $ ,/"2+ 262 . 26 77260" ? * + ' + ' 0 02+ 2 .9/ '" 34 * " 34

- $ , , "

vivo

RG = 200 kΩ+–

RD

RS

CC

+10 V

–10 V

CS

$&! (

+– R2

vi

Rin R1

CC1

RD

VDD = 20 V

vo

RS

RL

CC2

CS

$&! ((

+– R2

vi

R1

CC1

RS

VDD = 10 V

vo

RL

CC2

ii io

Ro

$&! (/

Page 62: Basic FET Amplifiers

, -!

(1 * $ ,/"2: 026 062 77060" 0 $ ! , "

( $ ,/"2:

? 06 0 /762 7" $ !

, 79:" 34 - & $$ )* +" 34 - & )* /7"

?:(2 $ ,/"28 1 $ ! ? 26 :62 77060" - :" $ ! , "

(5 * ,/"28" E 07 ' 7" $! * , 797" - " - ! ! * 2 ' "

:(6 $ ,/"28 ?

26 +62 7" - 277"- $ ! "

' $ ,/".7 : ? . 26 :62 7" 34

- " 34 - ! * $ ! $ $ * !"

+5 V

–5 V

vi

CC2voRG =

500 kΩRL =4 kΩIQ

+–

CC1

Ro

$&! (1

+5 V

–5 V

vi

CC2

RS

voRG =200 kΩ

RL =2 kΩ

+–

CC1

Ro

$&! (2

Page 63: Basic FET Amplifiers

* /

' * $ ,/".0" ! ! # " ! !

0

*

! !

0 *

:'( ,/".2 06

062 7" :6 .77 '"34 - 08 .6" 34 - $ ! , "

!% 1 .""#%! .8$&%

'' $ ,/".. 1 ? 06 .62 7" 34 - " 34 *

" 34 $ ! , "

'/ * , $ ,/".+" $ ? . 06 7:62 7" 34 - 78: /6" 34 -

V – = –5 V

V + = 5 V

vi

CC2

RL

vo

RG =200 kΩ

IQ

+–

CC1

Ro

$&! '

VDD

vi

CC2

RS RL

RGvo+

CC1

$&! '

+– R2

vi

R1CC1

RS

VDD

vO

Ri

Ro

$&! '(

Page 64: Basic FET Amplifiers

" 34 - ! : "

'1 /".+ ( ? 26 +62 7" ? 076 076 077 ' * 2 ' :" 34 026" 34 * " 34 - $ !

, "

' $ /".8 ( , ? . 26 262 7" ?

076 076 277 ' * 07 '" 34 -

. 076" 34 - $ ! , "

!% 2 "8! ;% :!,!

:'2 * 1 /".934" $ ? * 26 0

/762 7 )** 7:"E 076" 34 - $ ! , : $ " 34 - ! "

?'5 1 /"+.34

? 026 * 26 7:62 * 7062 * 77260" E 076" 34 - $ " 34 * ! " 34 -

$ ! "

'6 * ! " 0:6" % .6 7"5" -

$ "

/ ,/"+7 06 7:62 / * 06 * .762 /*" 7 " 34 * &

! ! " 34 - $ ! , $"

/ $ ,/"+0" 06 062 / * 06 * 7062 /*" 7 " E 96" 34 -

, -!

CC1

vi

vo

RS = 10 kΩ RD = 5 kΩ RL = 4 kΩ+–

CC2

V – = –5 V V + = +5 V

$&! ''

CC1

RL =2 kΩ

RG =50 kΩ

Ri =100 kΩ RD

vo

RS

CG

CC2

V + = +5 V V – = –5 V

io

Ri

Ro

$&! '/

VDD = 10 V

vO

vi+–

ML

MD

$&! /

Page 65: Basic FET Amplifiers

& ! * +6" 34 $ $ * ! $ ! , 00

*

"34 * $ ! * + '"

/( $ ,/"+0 ! , /"+0" 34 - $ ! * 07 '" 34 - $ "

!% 5 &%%$! "8!

?:/' ,/"+. ? 0 70622 0762 0 26 2 26 0 2 7"

? 076 0 + ' 277 '" 34 - 0 7+ 2 2 0 +6 2 :6" 34 * $ ! , " 34 - (

! "

:// ,/"+. ! , /"+." ? 076 0 0 ' 277 '

2 2 ' 2 7: '" 34 - $ /2 0 7+" 34 - ! 22 0" 34 - $ ! "

* /

RL

viCC

vo

VDD

+–

ML

+

VGG+

–vDSL

MDRo

$&! /

+–vi

CC vO

R2

Rin

R1

RD1

RD2RS1 CS1

CS2

VDD

M1 M2

RS2

$&! /'

Page 66: Basic FET Amplifiers

:/1 * ,/"+: 0 2 27762 0 2 756 0 2 7" 34 - 2 86 +77 '" 34 - ! 0 2

0" 34 * $ ! , "

/ ,/"+/ ? 0 2 +62 0 2 26 0 2 7" 34 - 0 20 2" 34 - 0 2" 34 - ! $ ! , "

:/2 /":7 ( ?

0 2 06 0 2 262 0 2 7" 34 E 02 ' 0 2 . :77 '" - . 0 2 2:6" 34 - $ ! , "

:/5 ! /":7 (

076 076" ? 0 2 +62 0 2 0:6 0 2 7" 34 E 2 ' 7"0" -

: 0 2 .:6" 34 - $ !$ "

!% 6 7 < "8!

/6 * ) /":. / . .6 77060" E 076" 34 - + /6" 34 - $"34 - $ ! , $!

! +"

1 ) ,/":7 ? 2 . 26 7" - , , "

:1 ) $

,/":0 ? 5 . +26 7" E 276 * 0/ '" - 26 0 2 077 ' $ 2 2"

, -!

+–

vi

vO

CC

R2

RinR1

M1 M2

RS1 =20 kΩ

RS2 =6 kΩ

VDD = 10 V

Ro

$&! /1

CC2 CC3vo

RS2 =10 kΩ

RS1 =10 kΩ

RD =5 kΩ

RL =2 kΩ

–10 V +10 V

+10 V

–10 V

viRG =400 kΩ

+–

CC1

M2

M1

$&! /

Page 67: Basic FET Amplifiers

?:1( * $ ) ,/":2 07 . :6 77060" E 026 * 7: '" 34 - 077 ' $ 2 2 34 - $ ! , "

1' $ ) $ ,/":. ? 2 . 08:6 7" 34 - "

34 - $ , , " 34 - ($ ! "

:1/ $ ) $ ,/":+ 5 . +6 7" - +

8:6 , . 0 2 +77 '"

* /

vi

CC

RD = 8 kΩ

VDD

vo

RS2 =250 Ω

RG =50 kΩ

RS1 =100 Ω RL =

4 kΩ

CC2

CS

iiio

+–

$&! 1

vi

CC1

Rin vo

RL

R2 RS

R1

RD

CC2

VDD

+–

iiio

$&! 1

vi

CC1

Rin

vo

RLR2 RS

R1

CC2

VDD

+–

ii

io

Ro

$&! 1(

+–vi

vo

R2 = 110 kΩ

R1 = 90 kΩ

RL =10 kΩ

RS = 5 kΩ

CC2

CC1

VDD = 10 V

iiio

$&! 1'

Page 68: Basic FET Amplifiers

. 4 49 7

11 * /"22 ! (

/"/" = ! $ $ $ ! "

1 = ! $ ! $

/"25" ! ( /"8"

12 $ /".+ ! ( /"07" = $

! 3' 4" ! "

15 , ( /"22 "

- $ ! " ! ( 2":6 & ! "

16 @ , /":5 ( /"2+"

:9 7

J1? "K

?: $ /"0/ ! ! 27 ! "

! :6 0 ' ? 756 0

+7 62 77060", )* ! & " - )* 70

?: $ /".8 ! 076 277 277" ? 0

.7 62 . 26

7" * : '" - ! '$$' :6"

, -!

vi

CC1

vOR2

RD

R1 RS

VDD = 20 V

+–

$&! 1/

Page 69: Basic FET Amplifiers

?:( $ /".2 " ! 026 ? 0:6 0

+7 62 7"

* 077" - 277% ! " $ "

?:' 1

/"+.34 ! :6 ? / 06 /* 26 0

+7 62 77060 7.:602"- $ ! , 277 " = $ & $

/"

?:/ /":7 ? 06 0

+762 7" - $

! 07" - ( ! "

* /

Page 70: Basic FET Amplifiers

Recommended