CX-49G-006.000-A0248 AVX Corporation, CX-49G-006.000-A0248 Datasheet - Page 20

• Manufacturer Part Number: CX-49G-006.000-A0248
• Description: Crystals 6KHZ
• Manufacturer: AVX Corporation
• Series: CX49Gr

Specifications of CX-49G-006.000-A0248

• Tolerance: 50 PPM
• Termination Style: SMD/SMT
• Operating Temperature Range: - 10 C to + 70 C
• Dimensions: 4.8 mm W x 12.3 mm L x 4.5 mm H
• Mounting Style: SMD/SMT
• Frequency: 6 KHz
• Frequency Stability: 50 PPM
• Load Capacitance: 12 pF
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

(2) Changes of load capacitance and oscillation frequency
unit changes with load capacitance C
the actual oscillation circuit, however, fine adjustments of
oscillation frequencies are carried out by varying C
capacitor or the like. The following figure shows an example of
load capacitance characteristics. The slope of the characteristics
varies depending on the frequency, shape, the number of overtone
mode, etc.
3. Crystal oscillation circuit
(1) C-MOS fundamental crystal oscillation circuit
The figure on the right shows a standard C-MOS inverter crystal
oscillation circuit for oscillating crystal unit with fundamental mode.
preventing frequency fluctuation, but Rx is not used in some
cases.
are changed under the condition of C
on the right.
condenser leads to a decrease of the negative resistance resulting
in increasing the possibility of oscillation failure.
resistance and is used to prevent oscillating by third Overtone
mode. In case of a bigger circuit of the negative resistance, there
is a case it is used to prevent the abnormal oscillation.
* Rx is an element to reduce excitation current of the crystal unit
Characteristics of the circuit when load capacitances C
As shown above, the series resonance frequency of the crystal
As shown above, the series resonance frequency of the crystal
It is not desirable that the excessive increase of the value of
Rd mainly adjusts frequency characteristics of the negative
1
L
= C
of the oscillation circuit. In
2
are shown in the figure
L
by the trimmer
1
and C
2
Variation of negative resistance with condenser capacity
(Ω)
(Ω)
Frequency characteristics of negative resistance
C-MOS fundamental crystal oscillation circuit
800
700
600
500
400
300
200
100
-100
-200
-500
-1K
-2K
-5K
-10K
0
0
-100
-200
-500
-1K
-2K
-5K
-10K
2
C
1
Xtal
0
4
10
R
f
= 1M
10
6
Condenser capasityC (C
Rx
20
20
Frequency(MHz)
8
C
Rd
1
C
=C
2
30
30
2
10
=10pF
Load capacity characteristic
Buffer
Handling Notes
1
=C
40
2
12
)(pF)
40
Resistance of Rd
3.5~6.9MHz=2.2kΩ
7.0~16MHz=220Ω
50
16.0MHz
10.0MHz
3.579545MHz
14
50
16
C
L
(pF)
60