QT325S-25.000MEIJ-T

Overview

The QT325S-25.000MEIJ-T is a surface-mount quartz crystal oscillator manufactured by QST, designed for precision timing applications. It operates at a fundamental frequency of 25 MHz with a standard package dimension of 3.2 x 2.5 x 0.7 mm. The component features a load capacitance of 18 pF and exhibits a frequency tolerance of ±10 ppm at 25°C. Frequency stability is maintained within ±20 ppm across the operating temperature range. The equivalent series resistance (ESR) is specified at 60 Ω, ensuring efficient energy transfer in resonant circuits.

Feature Summary

• Seam-sealed metal package construction provides robust environmental protection and mechanical stability.
• Low profile surface-mount design facilitates automated assembly and space-constrained PCB layouts.
• High frequency stability ensures reliable clock signals for digital systems across defined temperature ranges.

Applications

• Microcontroller unit (MCU) clock sources
• Digital signal processor (DSP) timing references
• Communication interface synchronization

Procurement Notes

Verify the specific suffix MEIJ-T against official QST documentation to confirm the exact electrical parameters, particularly the 18pF load capacitance and ±20ppm stability rating. Ensure compatibility with reflow soldering profiles specified in the datasheet. Confirm that the 60Ω ESR aligns with the target circuit's drive level requirements to prevent over-driving or oscillation failure.

Selection Notes

Select this component when a 25 MHz reference is required for compact surface-mount designs. The 18pF load capacitance must match the external capacitors in the oscillator circuit to achieve the specified ±10 ppm tolerance. Consider the -40°C to +85°C industrial temperature range if operation exceeds commercial limits. Verify that the 3.2x2.5mm footprint fits the available board space and that the 60Ω ESR is compatible with the driving gate's output impedance.

Part Context

This part belongs to the QT325S series of seam-sealed quartz crystals from QST. These components are engineered for high reliability in consumer electronics and industrial equipment. The series offers various frequency options and stability grades, with the MEIJ-T variant providing a balance of tight tolerance and cost-effectiveness for mass-produced devices requiring precise timing.

Replacement Considerations

Direct substitutes must match the 25 MHz frequency, 18pF load capacitance, and 3.2x2.5mm package dimensions. Check for identical ±10 ppm tolerance and ±20 ppm stability ratings. Verify that alternative manufacturers offer comparable 60Ω ESR values. Ensure the replacement part supports the same operating temperature range and mounting style without requiring layout modifications.