JIMMIE FOUTS HOUSTON COUNTY CAREER ACADEMY The 555 Integrated Circuit

Most Successful Chip Ever! The 555 is probably the most successful chip made Introduced in 1971 by Signetics Extremely popular in numerous circuits! Over 1 billion are manufactured annually Very versatile Robust although still sensitive to excessive “static” electricity Monolithic timing circuit Also available in low power CMOS versions

The 555 Chip Configuration A small circular indention on the chip body identifies Pin 1. Starting at top left (Pin 1) pins are numbered CCW

Static Sensitive Although robust, the 555, as with many other integrated circuits can be damaged when you touch them because your body may become charged with static electricity, from your clothing for example Static sensitive ICs, especially CMOS, are supplied in antistatic packaging with a warning label Limit handling of the pins It is usually adequate to earth ground your hands by touching a metal water pipe or metal window frame before handling

Physical Characteristics NE555 All integrated circuits require a power supply The 555 requires 4.5 to 16 VDC Temperature for operation 0 to 70 degrees C Typical trigger current.5 µA Typical rise/fall times 100 ns Output limited to about 200 ma Normally an 8 pin DIP

Potential Uses for the 555 Monostable (one shot) Oscillator Astable Oscillator Pulse Width Modulator Linear Ramp 50% Duty Cycle Oscillator

Another Configuration – The 556 The 556 is actually a dual 555 timer consisting of two 555 timer chips on one 14 pin integrated circuit Other configurations include three or four 555 timer chips within one integrated circuit