Intel 8080

Intel 8080

Closed and open Intel 8080 processor
General information
Launched	April 1974; 51 years ago (1974-04)
Discontinued	1990; 35 years ago (1990)[1]
Marketed by	Intel
Designed by	Intel
Common manufacturer	Intel
Performance
Max. CPU clock rate	2 MHz to 3.125 MHz
Data width	8 bits
Address width	16 bits
Architecture and classification
Technology node	6 μm
Instruction set	8080
Physical specifications
Transistors	4,500 or 6,000[2]
Cores	1
Package	40-pin DIP
Socket	DIP40
History
Predecessor	Intel 8008
Successor	Intel 8085
Support status
Unsupported

The Intel 8080 (pronounced "eighty-eighty") is Intel's second 8-bit microprocessor that played an important role in the evolution of early computing. Introduced in April 1974, the 8080 was an enhanced successor to the earlier Intel 8008 microprocessor, although without binary compatibility.^[3] Originally intended for use in embedded systems such as calculators, cash registers, computer terminals, and industrial robots,^[4] its robust performance soon led to adoption in a broader range of systems, ultimately helping to launch the microcomputer industry.

Several key design choices contributed to the 8080’s success. Its 40‑pin package simplified interfacing compared to the 8008’s 18‑pin design, enabling a more efficient data bus. The transition to NMOS technology provided faster transistor speeds than the 8008's PMOS while also simplifying interfacing by making it TTL compatible. An expanded instruction set and a full 16-bit address bus allowed the 8080 to access up to 64 KB of memory, quadrupling the capacity of its predecessor. A broader selection of support chips further enhanced its functionality. Many of these improvements stemmed from customer feedback, as designer Federico Faggin and others at Intel heard about shortcomings in the 8008 architecture.

The 8080 found its way into early personal computers such as the Altair 8800 and subsequent S-100 bus systems, and it served as the original target CPU for the CP/M operating systems. It also directly influenced the later x86 architecture which was designed so that its assembly language closely resembled that of the 8080, permitting many instructions to map directly from one to the other.^[5]

Originally operating at a clock rate of 2 MHz, with common instructions taking between 4 and 11 clock cycles, the 8080 was capable of executing several hundred thousand instructions per second. Later, two faster variants, the 8080A-1 and 8080A-2, offered improved clock speeds of 3.125 MHz and 2.63 MHz, respectively.^[6] In most applications, the processor was paired with two support chips, the 8224 clock generator/driver and the 8228 bus controller, to manage its timing and data flow.