Overview
IEC 60689:2008 - Measurement and test methods for tuning fork quartz crystal units in the range from 10 kHz to 200 kHz - defines measurement procedures and standard values for frequency control and selection of tuning‑fork quartz crystal units. This second edition expands the original 32 kHz wrist‑watch focus to a wider frequency band and modernizes accepted measurement techniques, providing manufacturers, test labs and designers with harmonized test methods and reference conditions.
Key topics and technical requirements
- Applied frequency range: 10 kHz to 200 kHz (extended from the first edition’s 32 kHz focus).
- Measurement methods:
- Method A (standard): Measurement using a vector network analyzer or vector impedance analyzer in a PI‑network configuration (IEC 60444 series based). Figures and test‑fixture diagrams are provided.
- Method B (permitted): Bridge method as a simpler alternative.
- Note: oscillator and Lissajous methods are not recommended for measuring equivalent circuit constants.
- PI network details: The PI network in this edition includes a transformer for impedance matching, differing from the composition in IEC 60444‑1.
- Load capacitance (standard values): 8 pF, 10 pF, 12 pF, 15 pF, 20 pF and 30 pF.
- Recommended drive level: 0.1 μW.
- Equipment/specs: Test equipment must cover 10 kHz–200 kHz. Tabled specifications include series resistance accuracy (1 %), signal level adjustment ranges (5 mV–1 V or 200 μA–20 mA rms) and spurious limits (40 dB max).
- Environmental and measurement conditions: Defined test conditions, frequency‑temperature characterization methods (turnover point, parabolic coefficient β), and load‑capacitance frequency characteristics are included.
Applications and users
IEC 60689 is primarily used by:
- Crystal manufacturers for production test, characterization and specification of tuning‑fork quartz units.
- Component test laboratories and quality control teams for standardized verification and acceptance testing.
- Oscillator and timekeeping device designers who need consistent frequency‑control data and load‑capacitance behavior.
- Suppliers and purchasers specifying component parameters for supply contracts or product datasheets.
Practical outcomes include consistent frequency specification, reliable equivalent circuit parameter measurement, and predictable temperature vs. frequency performance.
Related standards
Normative and referenced documents include:
Keywords: IEC 60689, tuning fork quartz crystal, 10 kHz to 200 kHz, measurement methods, PI network, bridge method, vector network analyzer, load capacitance, frequency‑temperature characteristics.