Chương 4: Fet potx

Chapter 4: FET Chapter 4: FET  Classification Classification  JFET JFET  Depletion MOSFET Depletion MOSFET  Enhancement MOSFET Enhancement MOSFET  CMOS CMOS – chapter 5 – chapter 5  Common configuration Common configuration  Biasing configuration Biasing configuration - chapter 6 - chapter 6  FET small signal analysis FET small signal analysis – chapter 9 – chapter 9 Classification Classification  JFET-Junction Field Effect Transistor JFET-Junction Field Effect Transistor • N-channel N-channel • P-channel P-channel  MOSFET-Metal Oxide Semiconductor FET MOSFET-Metal Oxide Semiconductor FET • Depletion—type: Depletion—type:  N and P channel N and P channel • Enhancement-type: Enhancement-type:  N and P channel N and P channel JFET JFET  Construction Construction  Operation Operation  Characteristic Characteristic  Transfer characteristics Transfer characteristics  Specification sheets Specification sheets  Important relationships Important relationships JFET - Construction JFET - Construction JFET - operation JFET - operation  V V GS GS =0, V =0, V DS DS >0 >0  V V GS GS =0 =0 JFET - operation JFET - operation  V V GS GS <0, V <0, V DS DS >0 >0  V V GS GS =0, V =0, V DS DS =V =V P P JFET - characteristic JFET - characteristic  I I G G =0A =0A (dòng cực cổng) (dòng cực cổng)  I I D D =I =I S S (dòng cực phát = dòng cực nguồn). (dòng cực phát = dòng cực nguồn).  I I D D =I =I DSS DSS (1-V (1-V GS GS /V /V GS(off) GS(off) ) ) 2 2 for JFET, DMOSFET (V for JFET, DMOSFET (V GS(off) GS(off) =V =V P P ) )  I I D D =k(V =k(V GS GS -V -V GSth GSth ) ) 2 2 for EMOSFET, k=I for EMOSFET, k=I Don Don /(V /(V GSon GSon -V -V T T ) ) JFET - characteristic JFET - characteristic P-channel, I P-channel, I DSS DSS =6mA, V =6mA, V P P =6V =6V N-channel, I N-channel, I DSS DSS =8mA, V =8mA, V P P =-4V =-4V Datasheet-2N5457-maximum rating Datasheet-2N5457-maximum rating Rating Rating Symbol Symbol Value Value Unit Unit Drain-Source voltage Drain-Source voltage V V DS DS 25 25 Vdc Vdc Drain-Gate voltage Drain-Gate voltage V V DG DG 25 25 Vdc Vdc Reverse G-S voltage Reverse G-S voltage V V GSR GSR -25 -25 Vdc Vdc Gate current Gate current I I G G 10 10 mAdc mAdc Device dissipation 25 Device dissipation 25 0 0 C C Derate above 25 Derate above 25 0 0 C C P P D D 310 310 2.82 2.82 mW mW mW/ mW/ 0 0 C C Junction temp range Junction temp range T T J J 125 125 0 0 C C Storage channel temp Storage channel temp range range T T stg stg -60 to -60 to +150 +150 0 0 C C Datasheet-2N5457-characteristics Datasheet-2N5457-characteristics Characteristic Characteristic Symbol Symbol Min Min Typ Typ Max Max Unit Unit V V G-S breakdown G-S breakdown V V (BR)GSS (BR)GSS -25 -25 Vdc Vdc I I gate reverse(Vgs=-15, Vds=0) gate reverse(Vgs=-15, Vds=0) I I GSS GSS -1.0 -1.0 nAdc nAdc V V G-S cutoff G-S cutoff V V GS(off) GS(off) -0.5 -0.5 -1.0 -1.0 Vdc Vdc V V G-S G-S V V GS GS -2.5 -2.5 -6.0 -6.0 Vdc Vdc I I D-zero gate volage D-zero gate volage I I DSS DSS 1.0 1.0 3.0 3.0 5.0 5.0 mAdc mAdc C C in in C C iss iss 4.5 4.5 7.0 7.0 pF pF C C reverse transfer reverse transfer C C rss rss 1.5 1.5 3.0 3.0 pF pF [...]... E-MOSFET Voltage-divider configuration Note:  VGS0, for EMOSFET Feedback biasing configuration  VDS = VDD-RDID  ID = IDSS(1-VGS/VGS(off))2 , VGS0, for E-MOSFET FET  Transconductance factor: • gm=ΔID/ΔVGS (S)  JFET: • gm=2IDSS(1-VGS/VP)/|VP| • gm0=2IDSS/|VP| • gm=gm0(1-VGS/VP)  FET. .. n-type, VGS0 MOSFET – transfer characteristic... Cin(Vds=10V,Id=2mA,f=140kHz) Ciss 5.0 pF CDS(Vdsub=10V,f=140KHz) Crss 5.0 pF RDS(Vgs=10V,Id=0,f=1KHz) Rds(on) 300 ohms Vds=10V,Vgs=0, 25C – 150C CMOS  CMOS=Complementary MOSFET  pMOS and nMOS on the same substrate  Can reduce size and power consumption of MOSFETs  Use mostly for IC  pMOS and nMOS ON/OFF operation  Example: inverter Configuration  Common source configuration  Common gate configuration  Common... Note: VGS>0, for E-MOSFET FET  Transconductance factor: • gm=ΔID/ΔVGS (S)  JFET: • gm=2IDSS(1-VGS/VP)/|VP| • gm0=2IDSS/|VP| • gm=gm0(1-VGS/VP)  FET output impedance: • Z0=rd=ΔVDS/ΔID FET small signal analysis  FET model: (a)  r∏ large, about n100-n1000 MΩ=>can ignore=> (b)  rD=Zout=∆VDS/∆ID • Can ignore if RD small => (c) Common source - CS CS – AC parameters  Zi = RG R1//R2 for (a), (b) for... N-channel depletion N-channel enhancement MOSFET - operation N-channel depletion VGS=0, VDS>0 N-channel enhancement VGS>0, VDS>0 MOSFET – transfer characteristic N-channel depletion N-channel enhancement MOSFET – transfer characteristic P-channel depletion P-channel enhancement Datasheet-2N4351-Depletion MOS Characteristic VDS breakdown Symbol Min Max V(BR)DSX 25 Unit Vdc ID-zero gate volage, IDSS 10 10 nAdc . Chapter 4: FET Chapter 4: FET  Classification Classification  JFET JFET  Depletion MOSFET Depletion MOSFET  Enhancement MOSFET Enhancement MOSFET  CMOS CMOS – chapter. relationships JFET - Construction JFET - Construction JFET - operation JFET - operation  V V GS GS =0, V =0, V DS DS >0 >0  V V GS GS =0 =0 JFET - operation JFET - operation  V V GS GS <0,. nguồn).  I I D D =I =I DSS DSS (1-V (1-V GS GS /V /V GS(off) GS(off) ) ) 2 2 for JFET, DMOSFET (V for JFET, DMOSFET (V GS(off) GS(off) =V =V P P ) )  I I D D =k(V =k(V GS GS -V -V GSth GSth ) ) 2 2 for EMOSFET, k=I for EMOSFET, k=I Don Don /(V /(V GSon GSon -V -V T T ) )