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BCE. BJT – Bipolar Junction Transistor Dua Type BJT Transistor: npnpnp npn E B C pnp E B C Cross Section B C E Symbol B C E Symbol Collector doping is.

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Presentasi berjudul: "BCE. BJT – Bipolar Junction Transistor Dua Type BJT Transistor: npnpnp npn E B C pnp E B C Cross Section B C E Symbol B C E Symbol Collector doping is."— Transcript presentasi:

1 BCE

2 BJT – Bipolar Junction Transistor Dua Type BJT Transistor: npnpnp npn E B C pnp E B C Cross Section B C E Symbol B C E Symbol Collector doping is usually ~ 10 6Collector doping is usually ~ 10 6 Base doping is slightly higher ~ 10 7 – 10 8Base doping is slightly higher ~ 10 7 – 10 8 Emitter doping is much higher ~ 10 15Emitter doping is much higher ~ 10 15

3 Rumusan Dasar BJT B C E IEIEIEIE ICICICIC IBIBIBIB - + V BE V BC V CE B C E IEIEIEIE ICICICIC IBIBIBIB - + V EB V CB V EC npn I E = I B + I C V CE = -V BC + V BE pnp I E = I B + I C V EC = V EB - V CB

4 DC  and DC   = Arus penguatan Common-emitter  = Arus penguatan Common-base  = I C  = I C  = I C  = I C I B I E I B I E Hubungan antara dua parameters tersebut adalah:  =   =   =   =     

5 BJT Example Konfigurasi Common-Base Transistor NPN +_ +_ Diketahui : I B = 50  A, I C = 1 mA Hitung : I E, , and  Penyelesaian: I E = I B + I C = 0.05 mA + 1 mA = 1.05 mA b = I C / I B = 1 mA / 0.05 mA = 20  = I C / I E = 1 mA / 1.05 mA =  Juga dapat dicari dengan  dengan rumus sebagai berikut.  =  = 20 =  =  = 20 =   ICICICIC IEIEIEIE IBIBIBIB V CB V BE E C B

6 Curve Transconductance BJT Transistor Tipe NPN V BE ICICICIC 2 mA 4 mA 6 mA 8 mA 0.7 V Arus Collector : I C =  I ES e V BE /  V T Transconductance: (slope of the curve) g m =  I C /  V BE I ES = Arus saturasi terbalik dari B-E Junction. B-E Junction. V T = kT/q = 26 mV T=300K)  = Coefisien emisi biasanya ~1 biasanya ~1

7 Modes of Operation Posisi terbaik pada daerah operasiPosisi terbaik pada daerah operasi Beroperasi sebagai penguatBeroperasi sebagai penguatActive: Saturation: Transistor berada sebagaimana pada posisi short circuit.Transistor berada sebagaimana pada posisi short circuit. Cutoff: Arus transistor nolArus transistor nol Transistor yang edial sebagaimana posisi saklar terbukaTransistor yang edial sebagaimana posisi saklar terbuka * Note: There is also a mode of operation called inverse active, but it is rarely used.

8 TigaTypes dari Bias BJT Bias transistor adalah kondisi tegangan dimana transistor tersebut bisa melakukan operasi (kerja). Bias Common-Base (CB) :input = V EB & I E output = V CB & I C Bias Common-Emitter (CE):input = V BE & I B output= V CE & I C Bias Common-Collector (CC):input = V BC & I B output = V EC & I E

9 Common-Base Although the Common-Base configuration is not the most common biasing type, it is often helpful in the understanding of how the BJT works. Emitter-Current Curves Saturation Region IEIEIEIE ICICICIC V CB Active Region Cutoff I E = 0

10 Common-Base Circuit Diagram: NPN Transistor +_+_ ICICICIC IEIEIEIE IBIBIBIB V CB V BE EC B V CE V BE V CB Region of Operation ICICICIC V CE V BE V CB C-B Bias E-B Bias Active IBIBIBIB =V BE +V CE ~0.7V  0V Rev.Fwd. SaturationMax~0V~0.7V -0.7V

11 Common-Emitter Circuit Diagram +_ V CC ICICICIC V CE IBIBIBIB Collector-Current Curves V CE ICICICIC Active Region IBIBIBIB Saturation Region Cutoff Region I B = 0 Region of Operation Description ActiveArus basis yang kecil mengontrol arus colektor yang besar SaturationV CE(sat) ~ 0.2V, V CE increases with I C CutoffPada kondisi I B mendekati 0, edialnya, I C juga sama dengan 0.

12 Common-Collector Emitter-Current Curves V CE IEIEIEIE Active Region IBIBIBIB Saturation Region Cutoff Region I B = 0 The Common- Collector biasing circuit is basically equivalent to the common-emitter biased circuit except instead of looking at I C as a function of V CE and I B we are looking at I E. Also, since  ~ 1, and  = I C /I E that means I C ~I E

13 Eber-Moll BJT Model The Eber-Moll Model for BJTs is fairly complex, but it is valid in all regions of BJT operation. The circuit diagram below shows all the components of the Eber-Moll Model: E C B IRIRIRIR IFIFIFIF IEIEIEIE ICICICIC IBIBIBIB RIERIERIERIE RICRICRICRIC

14 Eber-Moll BJT Model  R = Common-base current gain (in forward active mode)  F = Common-base current gain (in inverse active mode) I ES = Reverse-Saturation Current of B-E Junction I CS = Reverse-Saturation Current of B-C Junction I C =  F I F – I R I B = I E - I C I E = I F -  R I R I F = I ES [exp(qV BE /kT) – 1]I R = I C [exp(qV BC /kT) – 1]  If I ES & I CS are not given, they can be determined using various BJT parameters. BJT parameters.

15 Small Signal BJT Equivalent Circuit The small-signal model can be used when the BJT is in the active region. The small-signal active-region model for a CB circuit is shown below: iBiBiBiB rrrr iEiEiEiE iCiCiCiC iBiBiBiB BC E r  = (  + 1) *  V T I E I  = 1 and T = 25  C r  = (  + 1) * I E I E Recall:  = I C / I B

16 The Early Effect (Early Voltage) V CE ICICICIC Note: Common-Emitter Configuration -V A IBIBIBIB Green = Ideal I C Orange = Actual I C (I C ’) I C ’ = I C V CE + 1 V A V A

17 Early Effect Example Given:The common-emitter circuit below with I B = 25  A, V CC = 15V,  = 100 and V A = 80. Find: a) The ideal collector current b) The actual collector current Circuit Diagram +_ V CC ICICICIC V CE IBIBIBIB b = 100 = I C /I B a) I C = 100 * I B = 100 * (25x10 -6 A) I C = 2.5 mA b) I C ’ = I C V CE + 1 = 2.5x = 2.96 mA V A 80 V A 80 I C ’ = 2.96 mA

18 Breakdown Voltage The maximum voltage that the BJT can withstand. BV CEO =The breakdown voltage for a common-emitter biased circuit. This breakdown voltage usually ranges from ~ Volts. BV CBO = The breakdown voltage for a common-base biased circuit. This breakdown voltage is usually much higher than BV CEO and has a minimum value of ~60 Volts. Breakdown Voltage is Determined By: The Base WidthThe Base Width Material Being UsedMaterial Being Used Doping LevelsDoping Levels Biasing VoltageBiasing Voltage

19 Sources Dailey, Denton. Electronic Devices and Circuits, Discrete and Integrated. Prentice Hall, New Jersey: (pp ) Prentice Hall, New Jersey: (pp ) 1 Figure 3.7, Transconductance curve for a typical npn transistor, pg 90. Liou, J.J. and Yuan, J.S. Semiconductor Device Physics and Simulation. Plenum Press, New York: Plenum Press, New York: Neamen, Donald. Semiconductor Physics & Devices. Basic Principles. McGraw-Hill, Boston: (pp ) McGraw-Hill, Boston: (pp ) Web Sites


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