7555IPA

The CONTROL VOLTAGE terminal in the ICM7555 and ICM7556 timers allows for the control of the two trip voltages for the THRESHOLD and TRIGGER internal comparators. This feature provides the possibility of oscillation frequency modulation in the astable mode or even inhibition of oscillation, depending on the applied voltage. In the monostable mode, delay times can be changed by varying the applied voltage to the CONTROL VOLTAGE pin.

The improved parameters of the ICM7555 and ICM7556 timers compared to the standard SE/NE 555/6 and 355 timers include low supply current, wide operating supply voltage range, low THRESHOLD, TRIGGER, and RESET currents, no crowbarring of the supply current during output transitions, higher frequency performance, and no requirement to decouple CONTROL VOLTAGE for stable operation. These timers are stable controllers capable of producing accurate time delays or frequencies. The ICM7556 is a dual ICM7555, with the two timers operating independently of each other, sharing only V+ and GND. In the one-shot mode, the pulse width of each circuit is precisely controlled by one external resistor and capacitor. For astable operation as an oscillator, the free-running frequency and the duty cycle are both accurately controlled by two external resistors and one capacitor. The circuits are triggered and reset on falling (negative) waveforms, and the output inverter can source or sink currents large enough to drive TTL loads or provide minimal offsets to drive CMOS loads.