lecture35

Lecture35 - 6.720J/3.43J Integrated Microelectronic Devices Spring 2007 Lecture 35-1 Lecture 35 Bipolar Junction Transistor(cont May 3 2007

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Unformatted text preview: 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 35-1 Lecture 35 - Bipolar Junction Transistor (cont.) May 3, 2007 Contents: 1. Current-voltage characteristics of ideal BJT (cont.) Reading material: del Alamo, Ch. 11, § 11.2 (11.2.1) Cite as: Jesús del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 35-2 Key questions • How does the BJT operate in other regimes? • How does a complete model for the ideal BJT look like? Cite as: Jesús del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 35-3 1. Current-voltage characteristics of ideal BJT (cont.) Forward-active regime ( V BE > , V BC < 0) Summary of key results: W B << L B n-Emitter p-Base n-Collector I E <0 I B >0 I C >0 V BE > 0 V BC < 0 qV BE I C = I S exp kT I S qV BE I B = (exp − 1) β F kT qV BE I S qV BE I E = − I C − I B = − I S exp − (exp − 1) kT β F kT Cite as: Jesús del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 35-4 • Current gain 2 n i D B I C N B W B N E D B W E β F 2 = I B n i D E N B D E W B N E W E To maximize β F : • N E N B • W E W B (for manufacturing reasons, W E W B ) • want npn , rather than pnp because this way D B > D E β F hard to control ⇒ if β F is high enough ( > 50), circuit techniques effectively compensate for this. Cite as: Jesús del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 35-5 Cite as: Jesús del Alamo, course materials for 6.720J Integrated Microelectronic Devices, Spring 2007. MIT OpenCourseWare (http://ocw.mit.edu/), Massachusetts Institute of Technology. Downloaded on [DD Month YYYY]. 6.720J/3.43J - Integrated Microelectronic Devices - Spring 2007 Lecture 35-6 • Equivalent circuit model C E qV BE I S exp B kT I S (exp qV BE -1) β F kT qV BE I C = I S exp kT...
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This note was uploaded on 09/24/2010 for the course EECS 6.720J taught by Professor Jesúsdelalamo during the Spring '07 term at MIT.

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Lecture35 - 6.720J/3.43J Integrated Microelectronic Devices Spring 2007 Lecture 35-1 Lecture 35 Bipolar Junction Transistor(cont May 3 2007

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