CX-2520SB Ver la hoja de datos (PDF) - Kyocera Kinseki Corpotation
Número de pieza
componentes Descripción
Fabricante
CX-2520SB Datasheet PDF : 27 Pages
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Handling Notes
Vcc
C4
R1
0.01
C2
C1
Ct
R2
C5
OUT
C3
R3
Select each circuit constant so that the adjustment ranges of upper and lower frequencies of this circuit are even on the
basis of the frequency of a single crystal unit measured using a specified load capacity, and that the margin of ±8 to 10 10-6
of the room temperature deviation of the crystal unit can be reserved.
To prevent the decrease in the negative resistance, always connect the crystal unit to the base of the transistor. For
transistors used for oscillation circuits, hfe and fT are important.
To obtain the large negative resistance with small current consumption, select a transistor for high frequency amplification
with hfe of over 250 and fT of 1GHz or more.
(7) Transistor third overtone oscillation circuit
①The resonance circuit comprised of L2 and C3 is required on the emitter side for preventing fundamental mode crystal
oscillation. Set the resonance frequency to a value higher than the intermediate between fundamental wave frequency and
third overtone frequency.
②Use L1, referred to as an elongation coil, to connect the load capacitance of the oscillation circuit in series. R1 prevents
self-excited oscillation by L1. Since it is difficult in general to design the oscillation circuit having adequate negative
resistance in the overtone oscillation frequency band, there are no other effective means of obtaining adequate oscillation
margin except for preventing the increase of load resonance resistance RL of the crystal unit.
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