HC49USM-FF5F18-4.000MHZ

Crystals Overview

The ILSI HC49USM-FF5F18-4.000MHZ is a parallel fundamental quartz crystal operating at a nominal frequency of 4 MHz. It utilizes the HC-49/US surface-mount package with dimensions of 13.3 mm x 4.7 mm. The component features a load capacitance of 18 pF and a frequency tolerance of ±30 ppm. It exhibits a maximum equivalent series resistance (ESR) of 150 Ohms and supports a drive level of 1 mW. The unit is designed for through-hole or SMD mounting, compliant with RoHS standards, and operates within a temperature range of -40°C to +85°C.

Crystals Feature Summary

• AT-cut quartz construction for stable oscillation
• Surface-mount compatible metal can design
• Lead-free processing compatibility

Crystals Applications

• T1/E1 system clocking
• Sonet/SDH synchronization
• General-purpose microcontroller timing

Crystals Procurement Notes

Verify the specific suffix FF5F18 against the manufacturer's current datasheet to confirm exact electrical tolerances and aging rates. Ensure the ordering part number matches the required frequency stability and package variant. Confirm RoHS compliance status if lead-free processing is mandatory for the assembly line. Cross-reference the ESR value with circuit requirements to prevent over-driving the crystal.

Crystals Selection Notes

Select this component when a standard 4 MHz reference is required in a compact surface-mount footprint. The 18 pF load capacitance must match the oscillator circuit's external capacitors. Verify that the 150 Ohm ESR limit aligns with the host oscillator's drive strength capabilities. Consider the -40°C to +85°C range for industrial environments requiring wider thermal operation than commercial grades.

Crystals Part Context

This part belongs to the HC49USM series from ILSI America, which provides cost-effective quartz crystals for high-volume consumer and industrial electronics. The HC-49/US form factor is widely adopted for its balance of size and performance. This specific model represents a standard frequency option within the broader catalog of parallel resonant crystals offered by the manufacturer.

Crystals Replacement Considerations

Direct substitutes include other manufacturers' HC-49/US 4 MHz crystals with matching 18 pF load capacitance and ±30 ppm tolerance. Verify pin compatibility and physical dimensions before substitution. Check for equivalent ESR and drive level specifications to ensure circuit stability.