Digital i cs

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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 functionsChips from same logic family can be interconnected to perform logic functionChips from different logic families may not be compatible

Digital ICs

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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 speedlow power consumption

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Small to medium scale integration ------TTL was the choice

TTL was largely replaced by CMOS in 1990s

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Digital ICsBipolar Logic ---- Diodes and transistorsDiode 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 speedBiCMOS 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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CMOS logic ------ logic circuit operates on 5 V power supply

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Various Series within CMOS family

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TTL Logic

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Various Series within TTL family

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DIODE Logic

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Diode AND gate

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Bipolar Junction Transistors

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Mode EBJ CBJ

Active Forward ReverseCutoff Reverse ReverseSaturation Forward Forward

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Storage time --- Propagation delay

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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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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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Transistor-transistor logic

Multiple-emitter transistor

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DTL Gates