1. General description
The ICM7555 is a CMOS timer providing significantly improved performance over the
standard NE/SE555 timer, while at the same time being a direct replacement for those
devices in most applications. Improved parameters 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.
The ICM7555 is a stable controller capable of producing accurate time delays or
frequencies.
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. Unlike the NE/SE555 device, the CONTROL_VOLTAGE terminal need not
be decoupled with a capacitor. The TRIGGER and RESET inputs are active LOW. The
output inverter can source or sink currents large enough to drive TTL loads or provide
minimal offsets to drive CMOS loads.
2. Features
n Exact equivalent in most applications for NE/SE555
n Low supply current: 80 µA (typical)
n Extremely low trigger, threshold, and reset currents: 20 pA (typical)
n High-speed operation: 500 kHz guaranteed
n Wide operating supply voltage range guaranteed 3 V to 16 V over full automotive
temperatures
n Normal reset function; no crowbarring of supply during output transition
n Can be used with higher-impedance timing elements than the NE/SE555 for longer
time constants
n Timing from microseconds through hours
n Operates in both astable and monostable modes
n Adjustable duty cycle
n High output source/sink driver can drive TTL/CMOS
n Typical temperature stability of 0.005 % / °C at 25 °C
n Rail-to-rail outputs
ICM7555
General purpose CMOS timer
Rev. 02 — 3 August 2009 Product data sheet
