BJT DC AC

BJT DC AC
CMOS8¤>nO Lecture 4, Sept. 30, 2003
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1. BJT device structure
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2. DC characteristics
3. ac small signal equivalent circuit
4. Frequency response
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1. Ch. 1, P. R. Gray and R. G. Meyer, “Analysis and Design of
Analog Integrated Circuits,” 3rd ed., 1977, John Wiley & Sons,
Inc.
BJT Device Structure
BJT Cross-section showing the parasitics 2/19




Figure 1: BJT cross-section
DC Characteristics (1st-order)
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Forward-active operation region of an npn BJT.
The collector current,
VBE qADnnp0
IC = IS exp , IS =