BJTs & FETsA.
311311::
20020055--20062006
22::
BJTs & FETsA.
EmitterBase
Collector
Intrinsic BJT
BJTs & FETsA.
intrinsic transistor pn ,
o (minority charge)
(. Punchthrough p-n n-p)
BJTs & FETsA.
npn
EB C
BJTs & FETsA.
. , .
. . C
BJTs & FETsA.
(, ) (Vbe=0, Vbc=0)
BJTs & FETsA.
(, ) (Vbe>0, Vbc
BJTs & FETsA.
: x=0 x=WB :
( )
=kTqVnn BEpBpB exp0 0
( ) 0=BpB Wn :
( ) ( )
=
BpBpB W
xnxn 10
:
( ) ( )B
pBn
pBnnB W
nqD
dxxdn
qDJ0==
BJTs & FETsA.
:
:
( )
===kTqVn
WDqAA
Wn
qDAJI BEpBB
nEE
B
pBnEnBC exp
00
=kTqVISI BEC exp
0pBB
nE nWDqAIS =
. IS (collector saturation current) .
BJTs & FETsA.
: x=-WE-xBE x=-xBE :
( )
=kTqVpxp BEnEBEnE exp0
( ) 0nEBEEnE pxWp = :
( ) ( )[ ] 00 1 nEE
BEnEBEnEnE pW
Xxpxpxp +
++=
:( ) ( )
E
nEBEnEp
nEppE W
pxpqDdxxdpqDJ 0==
BJTs & FETsA.
:
. :
:
== 1exp0 kTqVp
WD
qAAJI BEnEE
pEEpEB
= 1expkTqVISI BE
FB
BpaB
EndE
E
pnE
B
npB
F WDNWDN
WD
p
WDn
==0
0
. F (forward current gain) .
BJTs & FETsA.
K :
F C IBBpaB
EndEF WDN
WDN=
To F
NdE>>NaB WE>>WB To npn Dn>Dp
- : F C IB E-B (. surface recombination, depletion region recombination .), (Kirk Effect base push-out), high current injection .
BJTs & FETsA.
. . .
-. . .
. , . . .
BJTs & FETsA.
:
:
=kTqVISI BEC exp
= 1expkTqVISI BE
FB
F: 50-300
= 1expexpkTqVIS
kTqVISI BE
F
BEE
BJTs & FETsA.
:
:
=kTqVISI BCE exp
= 1expkTqVISI BC
RB
R: 0.1-5
= 1expexpkTqVIS
kTqVISI BC
R
BCC
BJTs & FETsA.
:
:
RF
BC
R
BE
FB
ISISkTqVIS
kTqVISI
+
=
1exp
1exp
.
:
BJTs & FETsA.
:
:
. . .
BJTs & FETsA.
+
= 1exp1expkTqVIS
kTqVISI BC
R
BE
FB
= 1expexpexpkTqVIS
kTqV
kTqVISI BC
R
BCBEC
=kTqV
kTqVIS
kTqVISI BCBEBE
FE expexp1exp
: Hybrid-
(Ebers-Moll)
BJTs & FETsA.
Mo : (VBE>0, VBC
BJTs & FETsA.
Mo : (VBE0)
() VBC,on0.5V
To
BJTs & FETsA.
Mo : (VBE>0, VBC>0)
() VC,satVBE,on-VBC,on=0.2V
BJTs & FETsA.
Mo : A (VBE
BJTs & FETsA.
) : Hybrid-
) : -Model
ECC
CCBCE
iii
iiiii
=
+=
+=+=1
/
1+= a
BJTs & FETsA.
() )
)
r0 ( )
(CBO)
n. uCB
BJTs & FETsA.
n+ Sub-Collector
p Base +
Collector Contact
EMITTER BASE
COLLECTOR
S.I. GaAs Substrate
n- Collector AlGaAs Emitter
Isolation Implant
BASE
EmitterBaseBaseCollector
HBT Epitaxial LayersS.I. GaAs Substrate
BJT
T (GaAs)
T (SiGe)
BJTs & FETsA.
PNP
pnp npn
BJTs & FETsA.
npn pnp
npn ( )
pnp ( )
BJTs & FETsA.
iC uBE uBE = 0,5V . , uBE 0,6V 0,8V
uBE C
mVo2
: Vbe (turn-on) . Si: Vbe,on0.7V GaAs: Vbe,on1.4V
BJTs & FETsA.
iC uCB VC VB ( )
( )
BJTs & FETsA.
iC uC uCE, ,
, . uCE VA . VA 50 100V Early
BJTs & FETsA.
iC uC () uBE uCE
iC uCE IS
.
+=
A
CEVu
SC VueIi T
BE
1
+A
CEV
u1
1
=
=
BEuCEC
O uir
C
AO IVr
BJTs & FETsA.
iC
BJTs & FETsA.
(, *1)
(, *2)
dc
-
CCCCCEC RIVVV ==
BC VV >
beBEBE uVu +=T
beV
u
SC eIi =Tbe Vu
BJTs & FETsA.
- ()
beT
CCC uV
IIi +=
dc ac
bembeT
Cc uguVIi ==
T
Cm V
Ig = (. ac ), , IC *2
BJTs & FETsA.
- () . ube dc VBE. , dc IC
iC uBE
BEBECC VuIi == ,
CC IiBE
Cm u
ig=
=
. ac dc ( ) ac *1
BJTs & FETsA.
be
T
CCCB uV
IIii 1+==
bBB iIi +=
dc ac bembeT
Cb u
guVIi ==
1
B
T
b
be
IV
iur ==
,
mgr =
BJTs & FETsA.
cCC
EiIii +==
eEE iIi +=
dc ac beT
Ebe
T
Cce uV
IuVIii ===
E
T
e
bee I
Viur ==
,
mme gg
ar 1=
( ) err 1+=
BJTs & FETsA.
cCC uVu +=
ac be
c
uu
( ) CcCCCCCCC RiIVRiV +== ( ) CcCCCC RiRIV =CcC RiV =
( ) cbeCmCbem uuRgRug ==
Cmbe
c Rguu =
*2
BJTs & FETsA.
(, )
, ,
ac dc, ac
1CC 2CC
EC
dc ac
BJTs & FETsA.
() ( )
rRR Bi //=rRB >>
rRi
oCo rRR //=oC rR
BJTs & FETsA.
()
( )
( )s
oLCu Rr
rRRA += ////
. RS . RS
BJTs & FETsA.
RE
BJTs & FETsA.
() ( )
ibBi
ii RRiuR //==
b
bib i
uR =
1+ei
ee
b
ee
ie Rr
uRrui +=+=
iu ( )( )ee Rr ++1
, , ( )1+
BJTs & FETsA.
() ()
( )( )eeBi RrRR ++= 1//
Cout RR
i
o
sig
i
sig
ou u
uuu
uuA ==
sigi
i
RRR+
( )LCe RRi //
( )eee Rri +( )( )ee
CL
sigi
i
RrRR
RRR
++//
1+r
( )( )ee
CL
RrRR
+//
BJTs & FETsA.
, ,
BJTs & FETsA.
() ( )
ei rR
Co RR = usig, . . RC
0=eieai
BJTs & FETsA.
()
Rsig RC
, ,
i
o
sig
i
sig
ou u
uuu
uuA ==
sige
e
Rrr+
( )LCc RRi //
mcee giri 1=
( ) ( )sige
LCLCm
sige
e
RrRRRRg
Rrr
++=////
BJTs & FETsA.
, ,
BJTs & FETsA.
()
ibBi RRR //=( ) ( )[ ]Loe Rrr //1 ++
++= 1//
// Bsig
eoo
RRrrR
BJTs & FETsA.
()
( )
i
o
sig
i
sig
ou u
uuu
uuA ==
sigi
i
RRR+
( )Loe Rri //
( )[ ]oLee rRri //+( ) 1////
BJTs & FETsA.
AA
iR
0=
LRi
om v
iG
( )( )
L
LoC
LoCmL
B
RRrR
RrRgRrR
////
//////
oR
s
ov v
vA
i
oi iiA
rrRB //
CoC RrR //
mg
( ) ( )( )
s
LoC
LoCmsB
B
RrRrR
RrRgRrR
rR
+
+
////////
////
( )( )( )emB
eeB
RgrRRrR
+++
1//1//
( ) ( ) CBs emoC RrRR
RgrR
++
//11//
em
m
Rgg
+ 1
( )( )[ ]
( )( )
( )( )
ee
LC
sem
LC
em
LCm
semB
emB
RrRR
RRgrRR
RgRRg
RRgrRRgrR
+++
++++
//1
//1
//1//1//
( ) ( )( )
L
LC
LCem
m
L
emB
RRR
RRRg
gR
RgrR
//
//1
1//
++
er
CR
mg
se
LC
RrRR
+//
L
LC
RRR //
( ) ( )[ ]LoeeB RrRrR ////1// ++
++ 1////
BseE
RRrR
( )( )( )
( ) sLL
eLoE
LoE
si
i
RrRR
rRrRRrR
RRR
++++
++
1
1////////
( )L
L
L
i
RRR
RR //1 +
Common Collector (Emitter Follower)
Common Base
Common Emitter with a Resistance Re
Common Emitter
: . ? .
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