 IC matching information (move to another page)
 Types of crystal cut
 Crystal unit equivalent circuit
 Frequencytemperature characteristics
 Test Circuit
 Output waveform
Types of crystal cut
Relation among crystal cut, mode of vibration and frequency range
Crystal Cut  Mode of vibration  Frequency range (kHz)  Capacitance ratio (C0/C1) 


AT  Thickness shear Fundamental  800~5,000 2,000~80,000 
450~300 220 

3rd overtone  20,000~90,000  n^{2} x 250 n: Overtone order 

5rd overtone  40,000~150,000  
7rd overtone  70,000~210,000  
BT  Thickness shear Fundamental  Thickness shear Fundamental  3,000~30,000  650 
XY  Flexural (Tuning fork)  16~150  425~800  
Extensional  600~3,000  400  
DT  Face shear  100~500  400  
CT  150~850  350  
SL  180~700  400 
Crystal unit equivalent circuit
A crystal unit in the main resonance frequency may be expressed as an electrical equivalent circuit: a circuit ordinarily composed of a series circuit consisting of an inductance, capacitance and resistance, and a capacitance connected in parallel to the series circuit as shown in the drawing.
Here, C0, which is commonly known as the shunt capacitance, comprises an interelectrode static capacitance to which the interterminal stray capacitance is added.
L1 and C1 are the equivalent constants of the crystal unit viewed as an electrical and mechanical oscillation system. Since both constants are determined by such factors as the type of cut, cutting angle, dimensions of the crystal blank, and construction of the electrodes, and are thus reproducible, crystal units can be manufactured with high precision.
R1, which denotes oscillation loss, is governed by conditions such as processing, storage, and dimensions of the crystal unit.
L1 is referred to as motional inductance, C1 is referred as motional capacitance, and R1 is referred as motional (series) resistance.
L1  Motional inductance 

C1  Motional capacitance 
R1  Motional(series)resistance 
C0  Shunt capacitance 
The electrical equivalent circuit, composed of L1, C1, R1 and C0, all of which are correlated, may be expressed by the following equation.
Shown below are some equations by which the performances of crystal units are expressed.
Frequencytemperature characteristics
Correlation between Crystal cutting angle and Frequencytemperature characteristics
Frequencytemperature characteristics of Tuning Fork Crystal Unit
Correlation between Crystal cutting angle and Frequencytemperature characteristics of ATcut Crystal Unit
Test Circuit
CSX750F/SSX750P SERIES
*1
390Ω  CSX750(FC) 

820Ω  SSX750(PT, PK) 
CMOS load
*2
50pF  CSX750(FC) 

30pF  CSX750(FB, FJ) 
25pF  SSX750(PC, PD) 
15pF  SSX750(PB, PJ), CSX252F 
Current Consumption
Output waveform
Oscillators output waveform
Measurement conditions
 Oscilloscope ・Input impedance: No less than 1 MΩ ・Input capacitance: No more than 15 pF ・Band width: No less than 500 MHz ・Make the grounding lead of the probe as short as possible.
 The CL includes the probe capacitance.
 Grounding should be singlepoint grounding.
 Supply voltage impedance should be as low as possible. Rise time from 0V to 0.9Vdd is to be more than 150 μs.
 Use an ammeter with small internal impedance.