CX MINIATURE CRYSTALS
800kHz
to 1.35MHz
LOW-PROFILE
MINIATURE
SMD CRYSTAL
EUROQUARTZ
Telephone:
+44(0)1460 230000
Fax:
+44(0)1460 230001
Email: sales@euroquartz.co.uk
Web: www.euroquartz.co.uk
CX-3-SM
Page
1 of 2
General Description
CX-3-SM quartz crystals are leadless devices designed for surface-
mounting on printed circuit boards or hybrid circuits. Hermetically
sealed in a rugged, ceramic package, the crystals are produced
utilizing a photo-lithographic process giving excellent repeatability
and consistent high quality.
Extensional mode
Ideal for use with microprocessors
Designed for low power applications
Compatible with hybrid or PCB mounting
Low ageing
Full military environmental testing available
Ideal for battery operated applications
Specification
800kHz 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
)**:
-0.035ppm/°C
2
Temperature Coefficient (k):
Note: Frequency (f) deviation from frequency (f0) @ turning point
temperature (t0) =
f-fo k(T-To)
=
fo
±5ppm max.
Ageing, first year:
1,000g peak, 0.3ms, ½ sine
Shock:
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
Max. Process Temperature:
Specifications are typical at 25°C unless otherwise indicated.
*
**
Closer frequency calibration available
Other turning point available
Frequency Range:
Functional Mode:
Calibration Tolerance*:
D
(TO P)
A
D
D
B
C
E
Outline
CX-3-SM Package Dimensions
Dimension
Typical
(mm)
Maximum
(mm)
A
B
C
D
E
Dimension
“C”
6.73
2.62
-
1.27
1.32
Glass Lid
(mm max.)
7.11
2.90
see below
1.52
1.57
Ceramic Lid
(mm max.)
SM1
SM2
SM3
1.47
1.52
1.60
1.75
1.80
1.88
Equivalent Circuit
Terminations
1
L
C
C
R
2
Designation
Termination
SM1
SM2
SM3
Gold Plated
Nickel, Silver Plated
Nickel, Solder Plated and Solder Dipped
L
Motional Inductance
C
Motional Capacitance C
Shunt Capacitance
R
Motional Resistance
CX MINIATURE CRYSTALS
800kHz
to 1.35MHz
LOW-PROFILE
MINIATURE
SMD CRYSTAL
EUROQUARTZ
Telephone:
+44(0)1460 230000
Fax:
+44(0)1460 230001
Email: sales@euroquartz.co.uk
Web: www.euroquartz.co.uk
CX-3-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 designed 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
C
CX-2
C
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.
Solder Pad Layout
1.78
3.05
5.46
Load Capacitance
The CX crystal calibration tolerance is influenced by the effective
circuit capacitances, specified as the load capacitance (C
L
.) C
L
is
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:
Packaging
CX-3H-SM- Bulk Pack (Standard)
- 16mm tape, 178mm or 330mm reels (Optional)
per EIA 481
- Tray Pack (Optional)
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
Order Code
CX-3
C = Ceramic Lid
Blank = Glass Lid
Frequency
-SM1
SM1
SM2
SM3
1.0MHz
( A
/
I
)
“S” if special
or custom design
Blank if standard
Calibration
Tolerance*
@ 25°C
A, B, C
*For other calibration
tolerances enter
figure in ppm
Temperature
Range:
C = Commercial
I = Industrial
M = Military
S = Specify
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