EURO
QUARTZ
Ultra-miniature Low Profile SMD
FEATURES
CX4 CRYSTAL
Fundamental Mode: 600kHz to 1.4MHz
Designed for low power applications
Overtone: 1.8432MHz to 2.5MHz
Smallest available package in this frequency range
Hermetically sealed, ceramic package
Excellent ageing characteristics
Full Military testing available
DESCRIPTION
CX4 crystals are leadless devices designed for surface mounting on
PCBs or hybrid substrates. The crystal has been designed for low
power applications.
OUTLINE & DIMENSIONS
SPECIFICATION
Specifications stated are typical at 25°C unless otherwise indicated.
Specifications may change without notice.
Parameters
Frequency (Hz):
Motional Resistance R1 (kΩ):
Motional Resistance R1 Max. (kΩ):
Motional Capacitance C1 (Ff):
Quality Factor Q (k):
Shunt Capacitance C0 (pF):
3.5
250
1.0
2.0
200
0.8
300
Fundamental
600K
1.0M
400
1.4M
600
3kΩ
1.3
150
0.7
3.5
80
1.0
1.5
45
0.8
Overtone
1.8432M
500
2.4576M
1000
Standard Calibration Tolerance
1
:
Drive Level:
Load Capacitance CL
2
:
Turning Point
2
:
Temperature Coefficient (k):
±500ppm (±0.5%)
±1000ppm (±0.1%)
±10000ppm (±1.0%)
3µW maximum
7pF
35°C
-0.035ppm/°C
2
Dim. H
SM1
SM2
SM3
SM4
SM5
Note: Frequency f at temperature T is related to frequency Fo at
turning point temperature To by:
f-fo
=k(T-To)
2
fo
Functional mode:
Extensional
Ageing, First year:
±5pppm maximum
Shock, survival:
1500g, 0.3ms, ½ sine
Vibration, survival:
20g rms, 10~2000Hz random
Operating Temperature Range
Commercial:
-10° to +70°C
Industrial:
-40° to +85°C
Military:
-55 to +125°C
Storage Temperature Range:
-55° to +125°C
Maximum Process Temperature:
+260°C for 20 seconds
1.
2.
Tighter tolerance available
Other values available
Glass
Lid
1.14
1.17
1.22
1.17
1.22
Ceramic
Lid
1.27
1.30
1.35
1.30
1.35
PACKAGING OPTIONS
CX4 crystals are available either tray packed (<250pcs) or tape and
reel (>250 pieces).
16mm tape, 178mm or 330mm reels (EIA 418).
HOW TO ORDER CX4 CRYSTALS
CX4 - S
-
C
-
SM1
-
1.8432M,
Frequency
K = kHz
M = MHz
500
Calibration
Tolerance
@25°C
(in ppm)
/
I
'S' if special,
custom design.
Otherwise leave
blank
Blank = glass lid
C = ceramic lid
Terminations
SM1 = Gold plated *
SM2 = Solder plated
SM3 = Solder dipped
SM4 = Solder plated *
SM5 = Solder dipped *
* = Lead free
Temp. Range
C = -10° ~ +70°C
I = -40° ~ +85°C
M = -55° ~ +125°C
S = Customer specified
EUROQUARTZ LIMITED Blacknell Lane CREWKERNE Somerset UK TA18 7HE
Tel: +44 (0)1460 230000 Fax: +44 (0)1460 230001 info@euroquartz.co.uk www.euroquartz.co.uk
EURO
QUARTZ
Ultra-miniature Low Profile SMD
CX4 CRYSTAL
Fundamental Mode: 600kHz to 1.4MHz
Overtone: 1.8432MHz to 2.5MHz
CRYSTAL EQUIVALENT CIRCUIT
TYPICAL APPLICATION FOR A
PIERCE OSCILLATOR
The low profile CX miniature crystal is ideal for use in small, high
density, battery operated portable products. The CX crystal designed
in a Pierce oscillator (single inverter) circuit provides very low current
consumption and high stability. A conventional Pierce oscillator is
shown above. The crystal is effectively inductive and in a Pi network
circuit with C
D
and C
G
provides the additional phase shift to sustain
oscillation. The oscillation frequency (f
O
) is 15 to 250ppm above the
crystal's resonant frequency (f
S
).
Drive Level
R
A
is used to limit the crystal's drive level by forming a voltage divider
between R
A
and C
D
. R
A
also stabilizes the oscillator against changes in
the amplifier's output resistance (R
O
). R
A
should be increased for
higher voltage operation.
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
L
=
C
D
x C
G
C
D
+ C
G
+ C
S
R1 Motional Resistance
C1 Motional Capacitance
L1 Motional Inductance
C0 Shunt Capacitance
CONVENTIONAL CMOS PIERCE OSCILLATOR CIRCUIT
Note: C
D
and C
G
include stray layout-induced capacitance to ground
and C
S
is the stray shunt capacitance between the crystal terminal. In
practice, the effective value of C
L
will be less than that calculated from
C
D
, C
G
and C
S
values because of the effect of the amplifier output
resistance. C
S
should be minimized.
The oscillation frequency (f
O
) is approximately equal to:
TERMINATIONS - PLATING
Designation
Termination
f
O
= f
S
Where
1+
C
1
2(C
O
+ C
L
)
SM1
SM2
SM3
SM4
SM5
Gold Plated (Lead Free)
Solder Plated
Solder Dipped
Solder Plated (Lead Free)
Solder Dipped (Lead Free)
F
S
= Series resonant frequency of the crystal
C
1
= Motional Capacitance
C
O
= Shunt Capacitance
EUROQUARTZ LIMITED Blacknell Lane CREWKERNE Somerset UK TA18 7HE
Tel: +44 (0)1460 230000 Fax: +44 (0)1460 230001 info@euroquartz.co.uk www.euroquartz.co.uk
PCB Design
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