Transcript Terminal Impedances Eq. 5.162 Eq. 5.198 Eq. 5.291 BJT & MOS Transistor [Chapter 4,5] [Chapter 6,7]

Terminal Impedances
Eq. 5.162
Eq. 5.198
Eq. 5.291
BJT & MOS Transistor
[Chapter 4,5]
[Chapter 6,7]
Analogous Devices
• Terminals
– “C”↔”D”
– “E” ↔”S”
– “B” ↔”G”
• Analogous Devices
– NPN ↔NMOS
– PNP ↔PMOS
Equivalent Circuit
Small Signal Model
Observations:
1. Both Q1 and Q2 are represented by the SAME small signal circuit.
2. To find the output resistance, find the terminal resistance by applying
a test voltage.
Big Picture
A Crude Metal Oxide
Semiconductor (MOS) Device
Positive charge attract
P-Type Silicon is
negative charges
slightly conductive.
to interface between
insulator and silicon.
The gate
draws no current!
V2 causes movement
of negative charges,
thus current.
V1 can control the
resistivity of the channel.
A conductive path is created
If the density of electrons is
sufficiently high.
Q=CV.
Resistance into the Base/Gate
Analogous Circuits
Three Derivations
Eq. 5.162
Eq. 5.198
Eq. 5.291