Evolution of implementation technologies
trend toward higher levels of integration
Discrete devices: relays, transistors (1940s-50s)
Discrete logic gates (1950s-60s)
Integrated circuits (1960s-70s)
- e.g. TTL packages: Data Book for 100’s of different parts
- Map your circuit to the Data Book parts
Gate Arrays (IBM 1970s)
- “Custom” integrated circuit chips
- Design using a library (like TTL)
- Transistors are already on the chip
- Place and route software puts the chip together automatically
- + Large circuits on a chip
- + Automatic design tools (no tedious custom layout)
- - Only good if you want 1000’s of parts