1. Digital ICs
1960’s Integrated circuits (Ics) –invention
IC -- multiple diodes, transistors, and other
components fabricated on a single chip
Logic family --- collection of different Integrated
chips that have similar input, output, and internal
circuit characteristics that perform different logic
functions
Chips from same logic family can be interconnected
to perform logic function
Chips from different logic families may not be
compatible
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2. Speed
Power consumption
cost
MOS --- 10 years before the BJT invention principles of
MOS are patented
lagged BJT in speed
but lower power consumption and higher level
of integration
mid-1980s Complementary MOS
Higher speed
low power consumption
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4. Small to medium scale integration ------TTL
was the choice
TTL was largely replaced by CMOS in 1990s
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5. Digital ICs
Bipolar Logic ---- Diodes and transistors
Diode logic (DL) ---- Diodes and resistors – to
perform logic operations
Transistor-transistor logic (TTL) --- transistors
both to perform logic functions and to boost output
drive capability.
Emitter-Coupled logic ---transistors as current
switches to achieve very high speed
BiCMOS logic - bipolar and MOS transistors-
input and logic circuits are CMOS for low power
consumption, outputs use bipolar transistors to
achieve higher driving capability
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24. The propagation delay of a signal path is the amount
of time it takes for a change in the input signal to
produce a change in the output signal.
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26. Setup time is the minimum time interval for which
the input signal must be stable prior to the sampling
event of the clock for the input signal to be
recognized correctly
hold time is the minimum time interval for which
the input signal must be stable following the
sampling event of the clock for the input signal to be
recognized correctly
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