74HCT5555D,118

Overview

The 74HCT5555D,118 is a high-speed Si-gate CMOS programmable delay timer with an integrated oscillator, manufactured by NXP USA Inc. It operates within the HCT logic family and is pin-compatible with low power Schottky TTL (LSTTL). The device features positive and negative edge triggering, retriggerable or non-retriggerable modes, and a divide-by range of 2 to 2^24. It supports RC, crystal, or external oscillator configurations and includes automatic power-on reset and Schmitt trigger action on both trigger inputs.

Feature Summary

• Programmable delay timer with oscillator supporting RC, crystal, or external clock sources
• Positive and negative edge triggered with retriggerable or non-retriggerable operation
• Divide-by range from 2 to 2^24 with direct reset capability
• Schmitt trigger action on both trigger inputs for noise immunity

Applications

• Motor control systems requiring precise timing
• Attic fan timers and domestic appliance controls
• Delay circuits in automotive applications
• Precision timing modules using digital timing accuracy

Part Context

This component belongs to the 74HC/HCT5555 series of programmable delay timers. It is specified in compliance with JEDEC standard no. 7A and is designed as a high-speed CMOS device compatible with LSTTL interfaces. The '118' suffix typically denotes tape and reel packaging, though specific packaging details are not explicitly confirmed in the provided source text beyond general series descriptions.

Replacement Considerations

Direct replacements must match the 74HCT5555 functionality, including the 16-pin SOIC package and HCT logic voltage levels (4.5V to 5.5V). Verify that substitute components support the same oscillator modes and divide-by ratios. Check manufacturer-specific variations in propagation delay and output current capabilities.