XGHC Electronics Crystal Resonators

HC-49/S is the traditional through-hole crystal package, most cost-effective and suitable for low-frequency applications (3.2-30MHz). It offers excellent mechanical stability and easy hand soldering. SMD packages (3225, 2520, 2016, 1612) are surface-mount devices for automated assembly and space-constrained designs. 3225 is most popular for general use. Smaller packages (2016, 1612) are for wearables and portable devices but have higher ESR. HC-49/S is ideal for prototypes and low-cost applications. SMD is preferred for production and compact designs.

Choose HC-49/S for cost-sensitive through-hole designs. Choose SMD packages for automated assembly and space-constrained applications.

Load capacitor calculation: CL = (C1 × C2) / (C1 + C2) + Cstray. Where CL is crystal load capacitance specification, C1 and C2 are external load capacitors, and Cstray is stray capacitance (typically 3-5pF from PCB traces and IC pins). For symmetric circuit with C1 = C2: C1 = C2 = 2 × (CL - Cstray). Example: For CL = 12pF and Cstray = 4pF: C1 = C2 = 2 × (12 - 4) = 16pF. Use standard capacitor values close to calculated value. XGHC provides load capacitance calculation tools and application notes. Incorrect load capacitors cause frequency shift and may prevent oscillation.

Use the load capacitance formula or contact FAE for calculation assistance. Verify with frequency measurement.

ESR (Equivalent Series Resistance) is the resistance of the crystal at resonance frequency. Lower ESR is better because: (1) Easier oscillation start-up - low ESR crystals start oscillating more reliably

(2) Lower power consumption - less energy lost in crystal

(3) Better frequency stability - less sensitivity to circuit variations

(4) Wider drive level margin - more tolerance to drive level variations. Typical ESR values: HC-49/S 10-100Ω, 3225 30-150Ω, 2520 40-200Ω, smaller packages have higher ESR. Your MCU/IC datasheet specifies maximum ESR. Select crystal with ESR well below maximum specification for reliable operation.

Select crystal with ESR well below your IC's maximum specification. Contact FAE for ESR requirement analysis.

Reliable crystal oscillation requires: (1) Correct load capacitors - match crystal CL specification

(2) Adequate drive level - sufficient but not excessive power (check crystal drive level spec)

(3) Low ESR crystal - select crystal with ESR well below IC maximum

(4) Proper PCB layout - keep traces short, good grounding, minimize stray capacitance

(5) Clean power supply - minimize noise on oscillator power

(6) Correct gain margin - ensure inverter has adequate gain for oscillation

(7) Temperature considerations - verify operation across full temperature range. XGHC provides oscillator circuit design guides. Test with actual hardware across voltage and temperature extremes.

Follow oscillator design best practices. Contact FAE for circuit review and troubleshooting.

Crystal aging is the gradual frequency change over time due to stress relaxation and mass transfer in the quartz. Typical aging rates: ±1 to ±5 ppm per year for standard crystals, better for high-quality units. Aging is logarithmic - most change occurs in first year. Factors affecting aging: temperature (higher temp accelerates aging), drive level (excessive drive increases aging), mechanical stress (mounting and thermal expansion). For designs requiring long-term accuracy: (1) specify tighter initial tolerance

(2) allow for calibration

(3) use TCXO for critical applications

(4) consider aging in system design. XGHC provides aging specifications for all crystal series.

Consider aging for long-term accuracy requirements. Use TCXO for critical timing applications.