SA555N

NE555 SA555 - SE555 General-purpose single bipolar timers Features ■ Low turn-off time ■ Maximum operating frequency greater than 500 kHz ■ Timing from microseconds to hours ■ Operates in both astable and monostable modes ■ Output can source or sink up to 200 mA ■ Adjustable duty cycle ■ TTL compatible ■ Temperature stability of 0.005% per °C Description The NE555, SA555, and SE555 monolithic timing circuits are highly stable controllers capable of producing accurate time delays or oscillation. In the time delay mode of operation, the time is precisely controlled by one external resistor and capacitor. For a stable operation as an oscillator, the free running frequency and the duty cycle are both accurately controlled with two external resistors and one capacitor. The circuit may be triggered and reset on falling waveforms, and the output structure can source or sink up to 200 mA. N DIP8 (Plastic package) D SO8 (Plastic micropackage) Pin connections (top view) 1 2 3 4 1 - GND 2 - Trigger 3 - Output 4 - Reset 8 7 6 5 5 - Control voltage 6 - Threshold 7 - Discharge 8 - VCC January 2012 Doc ID 2182 Rev 6 1/20 www.st.com 20 Schematic diagrams 1 Schematic diagrams Figure 1. Block diagram VCC+ THRESHOLD CONTROL VOLTAGE TRIGGER RESET 5kΩ COMP R FLIP-FLOP 5kΩ Q COMP S INHIBIT/ RESET 5kΩ S Figure 2. Schematic diagram NE555 - SA555 - SE555 DISCHARGE OUT 2/20 Doc ID 2182 Rev 6 NE555 - SA555 - SE555 Absolute maximum ratings and operating conditions 2 Absol...