ECEC Crystal Resonators

AT-cut crystals are used for frequencies above 1MHz, typically 1MHz to 200MHz. They use a specific cut angle of the quartz crystal that provides excellent frequency stability over temperature. AT-cut crystals are used for microcontroller clocks, communication systems, and high-frequency applications. Tuning fork crystals operate at 32.768kHz (2^15 Hz) and are shaped like a tuning fork. They are used exclusively for real-time clock (RTC) applications due to their low frequency and low power consumption. Tuning fork crystals have higher temperature coefficients than AT-cut crystals. Choose AT-cut for MHz frequencies, tuning fork for 32.768kHz RTC applications.

Choose AT-cut crystals for MHz frequencies. Choose tuning fork crystals for 32.768kHz real-time clock applications.

Package selection depends on application requirements: HC-49/S (11.0x4.7mm) - Through-hole mounting, excellent stability, lowest cost, suitable for industrial and legacy designs. SMD 7.0x5.0mm - Large SMD for better stability and easier handling. SMD 5.0x3.2mm - Popular mid-size SMD, good balance of size and performance. SMD 3.2x2.5mm - Compact SMD for space-constrained applications. SMD 2.0x1.6mm - Ultra-compact for wearable and portable devices. Smaller packages generally have slightly worse frequency stability and higher ESR. Larger packages offer better stability and lower ESR. Consider PCB space, assembly process, and performance requirements.

Choose package based on PCB space constraints, assembly method, and stability requirements. Contact us for package recommendations.

Load capacitance (CL) is the effective capacitance seen by the crystal in the oscillator circuit. It is critical because: 1) The crystal is designed to oscillate at the specified frequency only when loaded with the correct capacitance. 2) Incorrect load capacitance causes frequency offset - the crystal will oscillate at a frequency different from the specified value. 3) Load capacitance affects oscillator startup and stability. The load capacitance is determined by external capacitors C1 and C2 and stray capacitance: CL = (C1 * C2) / (C1 + C2) + Cstray. Common CL values are 8pF, 12pF, 16pF, and 20pF. Always match the crystal's CL to your circuit design for accurate frequency.

Match crystal load capacitance to your oscillator circuit design. Contact us for load capacitance calculation assistance.

ESR (Equivalent Series Resistance) is the internal resistance of the crystal. It affects oscillator performance in several ways: 1) Startup time - lower ESR allows faster oscillator startup. 2) Power consumption - lower ESR requires less drive power. 3) Oscillator stability - higher ESR may cause startup problems or oscillation failure. Typical ESR values: HC-49/S - 20 to 100 ohms depending on frequency. SMD crystals - 30 to 150 ohms depending on package size and frequency. Smaller packages generally have higher ESR. The oscillator circuit must provide sufficient gain to overcome the ESR. Check your MCU or oscillator IC specifications for maximum allowed ESR.

Choose crystals with ESR within your oscillator IC specifications. Contact us for ESR requirements.

Crystal aging is the gradual change in crystal frequency over time. It is caused by: 1) Mass transfer - contamination or material transfer on the crystal surface. 2) Stress relief - gradual relaxation of mounting stress. 3) Environmental effects - temperature, humidity, and mechanical stress. Typical aging rates: ±3ppm per year for standard crystals. ±1ppm per year for high-quality crystals. Aging is usually logarithmic - most change occurs in the first year. For high-precision applications, allow frequency margin for aging. Annual calibration may be required for critical applications. Store crystals in clean, stable environments to minimize aging.

Consider aging specifications for long-term accuracy requirements. Contact us for high-stability crystal options.