History
- 1947 — Transistor. The point-contact transistor demonstrated that amplification and switching could be performed in solid semiconductor material without a heated cathode.
- 1958 — Kilby's integrated circuit. Jack Kilby at Texas Instruments demonstrated a circuit in which multiple components were formed on one piece of semiconductor.
- 1959 — Planar process. Jean Hoerni at Fairchild developed the planar process, using silicon dioxide to protect junctions and enabling reliable surface interconnection.
- 1959 — Noyce's monolithic IC concept. Robert Noyce combined the planar process with deposited metal interconnections, providing a practical path to mass-produced monolithic ICs.
- 1959–1960 — MOSFET. Mohamed Atalla and Dawon Kahng demonstrated a successful MOS field-effect transistor at Bell Labs. MOS technology later became the dominant basis of dense digital integrated circuits.
- 1960s — RTL, DTL, and TTL. Early digital IC families evolved from resistor-transistor and diode-transistor logic into transistor-transistor logic. TTL offered useful speed, fan-out, and standardized 5 V operation.
- 1964 onward — 7400-series TTL. Standard logic functions became catalog commodities: NAND gates, flip-flops, counters, decoders, multiplexers, registers, and bus drivers.
- Late 1960s–1970s — CMOS grows. Complementary MOS logic provided very low static power and broad supply ranges. The 4000-series family became widely used.
- 1971 — Microprocessor. The Intel 4004 placed a programmable CPU onto a single chip, showing how far integration had moved beyond individual logic gates.
- 1970s–1980s — Memory and programmable logic. EPROM, DRAM, SRAM, PALs, and increasingly complex gate arrays reduced the number of separate packages needed for a system.
- 1980s onward — CMOS dominance. Lower power and scaling advantages made CMOS the preferred process for microprocessors, memories, ASICs, and most digital ICs.
- Modern era. A single package may now contain processor cores, memory, analog converters, communication interfaces, security hardware, clock generation, power management, and billions of transistors.
Why TTL is still worth learning
TTL is no longer the dominant way to build massive digital systems, but it provides a wonderfully concrete introduction to logic-family electrical behavior. Inputs draw current, outputs have clear drive limitations, and the 7400-series catalog maps neatly onto logic diagrams.
Why CMOS took over
CMOS could scale to much higher density with very low static power. As fabrication shrank transistor dimensions, CMOS became faster while preserving its integration and power advantages.