XR-L555

XR·L555 Micropower Timing Circuit GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM The XR-L555 is a stable micropower controller capable of producing accurate timing pulses. It is a direct replacement for the popular 555-timer for applications requiring very low power dissipation. The XR-L555 has approximately 1/15th the power dissipation of the standard 555-timer and can operate down to 2.7 volts without sacrificing such key features as timing accuracy and frequency stability. At 5-volt operation, typical power dissipation of the XR-L555 is 900 microwatts. The circuit contains independent control terminals for triggering or resetting if desired. In the monostable mode of operation, the time delay is controlled by one external resistor and one capacitor. For astable operation as an oscillator the free-running frequency and the duty cycle are accurately controlled with two external resistors and one capacitor as shown in Figure 2. The XR-L555 is triggered or reset on falling waveforms...