BS EN 60444-11:2010
$102.76
Measurement of quartz crystal unit parameters – Standard method for the determination of the load resonance frequency ƒL and the effective load capacitance CLeff using automatic network analyzer techniques and error correction
| Published By | Publication Date | Number of Pages |
| BSI | 2010 | 18 |
This part of IEC 60444 defines the standard method of measuring load resonance frequency fL at the nominal value of CL, and the determination of the effective load capacitance CLeff at the nominal frequency for crystals with the figure of merit M > 4.
M, according to Table 1 of IEC 60122-1:2002, is expressed in the following equation:
This gives good results in a frequency range up to 200 MHz. This method allows the calculation of load resonance frequency offset ΔfL, frequency pulling range ΔfL1,L2 and pulling sensitivity S as described in 2.2.31 of IEC 60122-1:2002. In contrary to the simple method of IEC 60444-4, this measurement technique avoids the use of physical load capacitors, and allows higher accuracy, better reproducibility and correlation to the application. It extends the upper frequency limit from 30MHz by the method of IEC 60444-4 to 200MHz approximately. This method is based on the error-corrected measurement technique of IEC 60444-5:1995, and therefore allows the measurement of fL and CLeff together with the determination of the equivalent crystal parameters in one sequence without changing the test fixture.
With this method the frequency fL is searched where the reactance XC of the crystal has the opposite value of the reactance of the load capacitance.
Furthermore this method allows to determine the effective load capacitance CLeff at the nominal frequency fnom.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 6 | English CONTENTS |
| 7 | 1 Scope 2 Normative references |
| 8 | 3 General concepts 3.1 Load resonance frequencies fLr and fLa 3.2 Effective load capacitance CLeff Figures Figure 1 – Admittance of a quartz crystal unit |
| 9 | 4 Reference plane and test conditions 4.1 General 4.2 Principle of measurement |
| 11 | Figure 2 – XC as a function of frequency (solid line) in the vicinity of fL Figure 3 – Level of drive of a crystal in a π-network vs. frequency |
| 12 | 4.3 Evaluation of errors |
| 13 | Figure 4 – Error of the load resonance frequency due to the inaccuracy of the measured voltages (dashed line) and the calibration resistances (soft line) Figure 5 – CL-error resulting from fLerror (due to inaccuracy of the measured voltages and the calibration resistances) for the same crystal as in Figure 4 |
| 14 | Figure 6 – Frequency error due to noise of the measured voltages Figure 7 – Error of load resonance frequency fL at 30 pF and 10 pF for typical equivalent parameters of quartz crystal units |
| 15 | Figure 8 – Error of CLeff for typical equivalent parameters of quartz crystal units |
| 16 | Bibliography |
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BS EN 60444-11:2010
Measurement of quartz crystal unit parameters – Standard method for the determination of the load…
