Lec9 - 6.012 Electronic Devices and Circuits Lecture 9 Bipolar Junction Transistor Models Outline Announcements Handout Lecture Outline and Summary

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6.012 - Electronic Devices and Circuits Lecture 9 - Bipolar Junction Transistor Models - Outline Announcements Handout - Lecture Outline and Summary First Hour Exam - Oct. 8, 7:30-9:30 pm; thru p-n diodes, PS #4 BJT operation and optimization: review FAR modeling Regions of operation: 1. Forward active; 2. Cut-off; 3. Saturation; 4. Reverse active Designing transistor structures: performance trade-offs, design rules Emitter diode model, b F model, a F model Ebers-Moll model for BJTs (using npn as the example) Modeling objective: Want i E (v BE ,v BC ) and i C (v BE ,v BC ) given struture Approach: Divide and conquer using superposition i E (v BE ,v BC )= i E (v BE , 0) + i E (0, v BC ) i C (v BE ,v BC C (v BE , 0) + i C (0, v BC ) (forward) (reverse) Forward (v BE , 0) and reverse (0, v BC ) solutions: defects ( d 's), I S 's, a 's Full model: I ES ,I CS , a F , a R (forward was also treated in recitations) Limitation of FAR models Base width modulation, the Early effect b variation with current: EB SCL recomb., HLI, and IR drops Clif Fonstad, 10/03 Lecture 9 - Slide 1
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npn BJT: Connecting with the n-channel MOSFET from 6.002 A very similar behavior, and very similar uses. D i D + MOSET i G v DS G + v GS S C i C + BJT i B v CE B + v BE E i B v CE > 0.2 V i 0.6 V FAR Cutoff I BS e qV BE /kT v BE v DS i D Saturation (FAR) Cutoff Linear or Triode i D K [v GS - V T (v BS )] 2 /2 a v CE i C 0.2 V Forward Active Region Cutoff Saturation i C b F i B Input curve Output family Clif Fonstad, 9/03 Lecture 9 - Slide 2
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npn BJT review: Approximate model for i E (v BE ,v BC ) and i C (v BE ,v BC ) in forward active region, v BE >0, v BC <0 p’, n’ (n i ~ 0 (v BC < 0) 0 (ohmic) 0 (ohmic) (n i 2 /N AB )(e qv
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This note was uploaded on 07/20/2009 for the course CSAIL 6.012 taught by Professor Prof.cliftonfonstadjr. during the Fall '03 term at MIT.

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Lec9 - 6.012 Electronic Devices and Circuits Lecture 9 Bipolar Junction Transistor Models Outline Announcements Handout Lecture Outline and Summary

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