XL7555

The XL7555 and XD7555 are CMOS RC timers providing significantly improved performance over the standard SE/NE 555 timers, while at the same time being direct replacements 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. Specifically, the XL7555 and XD7555 are stable controllers 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 regular bipolar SE/NE 555 devices, the Control Voltage terminal need not be decoupled with a 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.

Applications

• Precision timing
• Pulse generation
• Sequential timing
• Time delay generation
• Pulse width modulation
• Pulse position modulation
• Missing pulse detector

Key features

• Low supply current - XL/XD7555 ... 60μA
• Extremely low input currents ... 20pA
• High speed operation ... 1MHz
• Guaranteed supply voltage range ... 2V to 18V
• Temperature stability ... 0.005%/°C at +25°C
• Normal reset function - no crowbarring of supply during output transition
• Timing from microseconds through hours
• Adjustable duty cycle
• High output source/sink driver can drive TTL/CMOS
• Outputs have very low offsets, HIGH and LOW
• Pb-free (RoHS Compliant)