QT49S-12.288MAAJ-T

Overview

The QT49S-12.288MAAJ-T is a surface-mount quartz crystal oscillator manufactured by QST, designed for precise timing applications. It operates at a fundamental frequency of 12.288 MHz with a nominal load capacitance of 18 pF and a frequency tolerance of ±30 ppm at 25°C. The component features an equivalent series resistance (ESR) of 40 Ohms and functions within an operating temperature range of -20°C to +70°C. Housed in a standard SMD package measuring 12.7 x 4.8 x 3.8 mm, it utilizes the HC-49/US form factor adapted for surface mounting, ensuring compatibility with automated assembly processes.

Feature Summary

• Fundamental mode operation ensures stable oscillation at the specified 12.288 MHz frequency.
• Standardized SMD package dimensions facilitate direct integration into existing PCB layouts without mechanical redesign.
• RoHS compliant construction supports environmental regulations for electronic components.

Applications

• Consumer electronics clock sources
• Set-top box timing circuits
• Display panel synchronization

Procurement Notes

Verify the specific load capacitance requirement against the target circuit design, as the datasheet indicates an 18 pF nominal value which may differ from legacy designs using 12 pF or 20 pF. Confirm that the operating temperature range of -20°C to +70°C aligns with the environmental conditions of the end application. Ensure that the ESR specification of 40 Ohms is compatible with the oscillator circuit's drive level constraints to prevent overdriving or failure to start.

Selection Notes

Select this component when a 12.288 MHz reference is required for digital communication protocols such as serial interfaces or audio/video data streams. The ±30 ppm tolerance is suitable for general-purpose timing where high-precision synchronization is not critical. Consider the physical footprint compatibility if replacing through-hole HC-49/U crystals with surface-mount equivalents. Evaluate the thermal performance requirements to ensure the -20°C to +70°C range meets the operational environment standards.

Part Context

This part belongs to the QT49S series of surface-mount quartz crystals from QST, which are designed as drop-in replacements for traditional through-hole HC-49/U packages. The series offers various frequency options and load capacitances to support diverse timing needs in consumer and industrial electronics. The 12.288 MHz variant is commonly used in applications requiring baud rate generation for UART/RS-232 communications or sampling rates for audio processing.

Replacement Considerations

QT49S-12.288MAAE-T