558 Quad Timer datasheet
558 quad timer is a single timing device that can be used to generate four independent timing functions. 558 Output absorbs current. These highly stable and general-purpose controls can be used in monostable mode to generate accurate time delays of up to several hours in microseconds.
In the time delay operating mode, time is precisely controlled by one external resistor and one capacitor. Two of the four timer sections can be used for stable operation. The four timer sections of 558 do not require coupling capacitors when connected to tandem for sequential timing applications because the edges are triggered. Both units provide an output current capacity of 100mA.