4558

4558 is a designation used for a family of dual operational amplifiers in integrated-circuit form. The most common part numbers in this family include RC4558, NE4558, NJM4558, and LM4558. These devices are low-noise, general-purpose op-amps that house two amplifying stages in a single 8-pin package. They have been widely used in audio circuits, both in consumer electronics and in pro audio gear, as well as in signal conditioning, filters, and preamplification stages. Their popularity stems from a favorable combination of simplicity, low cost, and modest performance that suits many non-specialist analog tasks.

Pinout and form factor: like many dual op-amps, the 4558 family is offered in an 8-pin DIP and 8-pin surface-mount packages. In the standard configuration, pin 4 is the negative supply, pin 8 is the positive supply; each op-amp has an inverting and non-inverting input and an output (for op-amp A: pins 2, 3, 1; for op-amp B: pins 5, 6, 7).

Specifications and usage notes: the parts require a non-rail-to-rail supply and are typically operated from roughly +/-5 to +/-15 volts. They are not designed for single-supply operation at very low voltages or for high-speed, high-precision tasks. The devices exhibit low noise for their era and are known for robustness and ease of replacement in vintage gear. Variants differ mainly in screening and packaging; electrical behavior is largely compatible across RC4558, NE4558, NJM4558, and LM4558.

See also: Operational amplifier.