Crystal Parameters Explained

See also: Crystal summary  and Glossary of crystal terms

Below we give a brief explanantion of the more popular terms used when describing the specifications of quartz crystals. If you need further explanation, our engineers will be happy to help. Email: Engineering support at Golledge

Specification Code

To express normal parameters concisely we use a standard notation of the form:

A/B/C/D-E

where:

A = Calibration tolerance, expressed in parts per million (ppm)

B = Temperature stability over the temperature range, expressed in parts per million (ppm)

C = Negative end of operating temp range, which is normally symmetrical about +25C.

0 = 0 to +50C
10 = -10 to +60C
20 = -20 to +70C
30 = -30 to +80C
40 = -40 to +90C
55 = -55 to +105C

If the operating temperature range is not symmetrical about +25C we will specify both upper and lower limits i.e. ‘-55+125’. Ovened Crystals are signified by showing the oven temperature here and the figures ‘00’ for temperature stability.

D = Circuit condition. A number specifies parallel resonance with a load capacitance in pF. SR denotes Series Resonance.

E = Operating mode of crystal, where:

F = fundamental mode
3 = third overtone
5 = fifth overtone
7 = seventh overtone mode
9 = ninth overtone mode

Frequency and holder style are shown separately as are any special parameters such as C1,C0,L1, etc.

Examples

  • 30/50/10/30-F denotes a crystal with 30ppm calibration tolerance, a temperature stability of 50ppm over temperature range -10+60C, 30pF load capacitance and operating in fundamental mode.
  • 05/10/20/SR-3 denotes a crystal with 5ppm calibration tolerance, a temperature stability of 10ppm over temperature range -20+70C, series resonant and operating in third overtone mode.