CX MINIATURE CRYSTALS
760kHz
to 1.35MHz
LOW-PROFILE
SMD CRYSTAL
EUROQUARTZ
Telephone:
+44(0)1460 230000
Fax:
+44(0)1460 230001
Email: sales@euroquartz.co.uk
Web: www.euroquartz.co.uk
CX-2-SM
Page
1 of 2
General Description
The miniature CX-2-SM quartz crystal is a high quality leadless
device suitable for mounting on printed circuit boards or hybrid
substrates. The CX-2-SM is hermetically sealed in a rugged,
leadless ceramic package. The crystal has been designed for
surface-mounting on printed circuit boards or hybrid circuits. The
crystal is manufactured using a photo-lithographic process,
yielding consistently high quality production parts.
Extensional mode
High shock resistance
Designed for low-power applications
Compatible with hybrid or PC board packaging
Low ageing
Full military environmental testing available
Ideal for battery operated applications
Specification
760kHz to 1.35MHz
Extensional
A ±0.05% (±500ppm)
B ±0.1%
C ±1.0%
7pF
Load Capacitance:
5k
W
max.
Motional Resistance (R
):
1.2fF
Motional Capacitance (C
):
150k
Quality Factor (Q):
1.0pF
Shunt Capacitance (C
):
3
m
W max.
Drive Level:
35°C
Turning Point (T
)**:
Note: Frequency (f) deviation from frequency (f
0
) @ turning point
temperature (T
0
):
f-fo k(T-To)
=
fo
-0.035ppm/°C
2
Temperature Coefficient:
±5ppm max.
Ageing, first year:
1000g 0.3ms, ½ sine
Shock, survival:
10g rms, 20-1,000Hz random
Vibration, survival:
-10°~+70°C (commercial)
Operating Temperature:
-40°~+85°C (industrial)
-55°~+125°C (military)
-55°C~+125°C
Storage Temperature:
260°C for 20 seconds
Process Temperature:
Specifications are typical at 25°C unless otherwise indicated.
*
**
Tighter frequency calibration available
Other turning point available
Frequency Range:
Functional Mode:
Calibration Tolerance*:
1
(TO P)
A
I
G
2
H
3 F
D
Outline
B
C
E
Terminal 1 is electrically connected to terminal 3
CX-2-SM Package Dimensions
Dimension
Typical
(mm)
Maximum
(mm)
A
B
C
D
E
F
G
H
I
Dimension
“C”
6.60
2.39
-
0.89
1.50
1.27
2.67
3.94
5.33
Glass Lid
(mm max.)
6.99
2.74
see below
1.14
1.75
1.52
2.92
4.19
5.59
Ceramic Lid
(mm max.)
SM1
SM2
SM3
1.65
1.70
1.78
1.91
1.96
2.03
Equivalent Circuit
L
R
1
C
C
2
Solder Pad Layout
2.67
2.87
1
2
0.6
L
Motional Inductance
C
Motional Capacitance C
Shunt Capacitance
R
Motional Resistance
CX MINIATURE CRYSTALS
760kHz
to 1.35MHz
LOW-PROFILE
SMD CRYSTAL
EUROQUARTZ
Telephone:
+44(0)1460 230000
Fax:
+44(0)1460 230001
Email: sales@euroquartz.co.uk
Web: www.euroquartz.co.uk
CX-2-SM
Page
2 of 2
Circuit Design
Typical Pierce Oscillator Application
The low profile CX miniature surface-mount crystal is ideal for small,
battery operated portable products. The CX crystal design in a Pierce
oscillator (single inverter) circuit has a very low current consumption
with high stability. A conventional HCMOS Pierce oscillator circuit is
shown below. The crystal is effectively inductive and in a Pi network
with C
1
and C
2
which provides the additional phase-shift necessary
to sustain oscillation. The oscillation frequency (f
0
) is 15ppm to
150ppm above the crystal’s series resonant frequency (F
S
).
Conventional HCMOS Pierce Oscillator Circuit
R
B
Amplifier
Buffer
Osc.
Freq. (Fo)
C
5
R
)
Drive Level
R
A
is used to limit the crystal’s drive level by forming a voltage
divider between R
A
and C
1
. R
A
also stabilizes the oscillator against
changes in the amplifiers output resistance (R
0
). R
A
should be
increased for higher voltage operation.
C
CX-2
C
Load Capacitance
The CX crystal calibration tolerance is influenced by the effective
circuit capacitances, specified as the load capacitance (C
L
.) C
L
is
approximately equal to:
C x C
2
C
L
=
1
C
C
1
+ C
2
+
S
NOTE: C
1
and C
2
include stray layout capacitance to ground. C
S
is
the stray shunt capacitance between the crystal terminals. In
practice, the effective valus of C
L
will be less than that calculated
from C
1
, C
2
, and CS values due to the effect of the amplifier output
resistance. C
S
should be minimized.
The oscillation frequency (f
0
) is approximately equal to:
f
0
= f
S
1+
C
1
2(C
0
+ C
L
)
Where F
S
= Series resonant frequency of the crystal
C
1
= Motional Capacitance
C
0
= Shunt Capacitance
Terminations
Designation
Termination
Packaging
CX-2-SM -
Bulk Pack (Standard)
- 16mm tape, 178mm or 330mm reels (Optional)
per EIA 481
- Tray Pack (Optional)
SM1
SM2
SM3
Gold Plated
Nickel, Solder Plated
Nickel, Solder Plated and Solder Dipped
Order Code
CX-2
C = Ceramic Lid
Blank = Glass Lid
Frequency
-SM1
SM1
SM2
SM3
1.0MHz
( A
Calibration
Tolerance*
@ 25°C
A, B, C
/
I
)
“S” if special
or custom design
Blank if standard
*For other calibration
tolerances enter
figure in ppm
Temperature
Range:
C = Commercial
I = Industrial
M = Military
S = Specify
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