The 555 timer IC was first introduced around 1971 by the Signetics Corporation as the SE555/NE555 and was called "The IC Time Machine". It provided circuit designers with a relatively cheap, stable, and user-friendly integrated circuit. An IC timer is a semiconductor circuit that generates or sets timing for electronics circuits
IC timers are programmable timer chips. These timer chips function as single or multi function units. An IC timer works based on an external capacitor for determining on and off intervals in the output pulse. IC timers can work as up direction, down direction, or bi-direction
The LMC555 is a CMOS version of the industry standard 555 series general purpose timers. In addition to the standard package (SOIC, MSOP, and MDIP) the LMC555 is also available in a chip sized package (8 Bump micro SMD) using National's micro SMD package technology. The LMC555 offers the same capability of generating accurate time delays and frequencies as the LM555 but with much lower power dissipation and supply current spikes. When operated as a one-shot, the time delay is precisely controlled by a single external resistor and capacitor. In the stable mode the oscillation frequency and duty cycle are accurately set by two external resistors and one capacitor. The use of National Semiconductor's LMCMOS™ process extends both the frequency range and low supply capability.
The National LMC555CMX is a CMOS general purpose timer. It has an industrial temperature and comes in a SOIC-8 package.