Definition: legacy chip

A set of microminiaturized electronic circuits that were designed years ago and still made. Also called a "mature chip," legacy chips are not constructed using the latest semiconductor manufacturing processes because the products they are used in do not require the fastest performance available. In addition, compared to several hundred dollars for state-of-the-art CPUs and SoCs (aerospace and AI chips cost thousands), legacy chips can sell for only a few dollars. See CPU, SoC and AI chip.

Microcontrollers (MCUs) along with 8-bit and 16-bit central processing units (CPUs) are common examples of legacy chips. Used in appliances, automobiles, toys and non-state-of-the-art consumer electronics, the feature sizes of legacy chips are typically 30 nanometers and larger. In contrast, the feature sizes in the latest high-end CPUs and SOCs are in the 2 to 5 nanometer range. See microcontroller, process technology and chip manufacturing.

Legacy Chips Can Be Very Small

Legacy chips such as these microcontrollers (MCUs) from Microchip in Tempe, Arizona can be used in just about anything from a toaster to a child's toy. In quantity, they retail for around a dollar. Although small, they have 50 times more processing power than room-sized computers in the 1950s. See Microchip Technology and microcontroller.