18QHTF21-7.9954-PD

Overview

The 18QHTF21-7.9954-PD is a standard crystal oscillator (XO) manufactured by Mercury Electronics Ind. Co. Ltd. It operates at a frequency of 7.9954 MHz and utilizes an LVCMOS output interface. The device is designed for a supply voltage of 3.3V and features a Standby (Power Down) control function to manage power consumption. It is housed in a compact 4-SMD, No Lead package, suitable for surface-mount applications requiring precise timing signals.

Feature Summary

• LVCMOS output interface for digital logic compatibility
• Integrated standby control for power management
• Compact 4-SMD no-lead surface mount package

Applications

• General purpose timing circuits
• Embedded systems clock sources
• Consumer electronics timing references

Procurement Notes

Verify the specific frequency tolerance and load capacitance requirements against the target circuit design before procurement. Confirm that the 3.3V operating voltage aligns with the system power rails. Ensure the PCB footprint matches the 4-SMD, No Lead package dimensions provided in the official datasheet to guarantee proper soldering and mechanical stability during assembly.

Selection Notes

Select this component when a low-cost, standard frequency XO is required for non-critical timing applications. The LVCMOS output simplifies interfacing with standard logic families. Consider the 3.3V supply constraint and the availability of the standby pin if power efficiency is a secondary concern. Verify environmental operating ranges match the intended deployment conditions.

Part Context

This part belongs to the 18QHTF21 series from Mercury Electronics, which offers various standard frequencies in a small form factor. The series supports both 1.8V and 3.3V variants, with the -PD suffix indicating the specific package and lead-free status. It serves as a basic timing solution compared to higher-performance TCXO or VCTCXO options.

Replacement Considerations

Direct replacements must match the 7.9954 MHz frequency, 3.3V supply, LVCMOS output, and 4-SMD package. Cross-reference with other manufacturers offering identical pinouts and electrical characteristics to ensure functional equivalence without redesigning the host circuit.