The ICM7555 and ICM7556 are CMOS RC timers that offer significantly improved performance over the standard SE/NE 555/556 and 355 timers while directly replacing these devices in most applications. Improved parameters include low power supply current, wide operating power supply voltage range, low threshold, trigger and reset current, no blocking of power supply current during output transition, higher frequency performance, and no need to decouple control voltage for stable operation. Specifically, the ICM7555 and ICM7556 are stabilization controllers capable of producing precise time delays or frequencies.
Function diagram
The ICM7556 is a dual ICM7555. The two timers work independently of each other and share only V+ and GND. In single-lens mode, the pulse width of each circuit is precisely controlled by an external resistor and capacitor. For stable operation as an oscillator, both the free running frequency and duty cycle are precisely controlled by two external resistors and a capacitor.
Schematic Diagram
Unlike conventional bipolar SE/NE 555/556 devices, the control voltage terminals do not require capacitance decoupling. The circuit triggers and resets when the (negative) waveform drops, and the output inverter can either source or converge a current large enough to drive the TTL load, or provide minimal offset to drive the CMOS load.
Pin Configurations
