CX4-EXT Datasheet, PDF (1/3 Pages) IQD Frequency Products Ltd – Quartz Crystal Specification

ISSUE 1; January 2016
Description
STATEK’s CX4 quartz crystals are hermetically sealed in an
ultra-miniature low profile surface mount ceramic package.
This high quality quartz resonator forms the basis of a stable
oscillator.
-C SM1 Gold Plated (lead free) ceramic lid
-C SM4 Solder Plated (lead free) ceramic lid
-C SM5 Solder Dipped (lead free) ceramic lid
-SM1 Gold Plated (lead free) glass lid
-SM4 Solder Plated (lead free) glass lid
-SM5 Solder Dipped (lead free) glass lid
The CX4 family of surface mount crystals are ideal for small,
high density, battery operated portable products. The CX4
crystal designed in a Pierce oscillator (single inverter) circuit
provides very low current consumption and high stability.
A conventional CMOS Pierce oscillator circuit is shown below.
The crystal is effectively inductive and in a PI network circuit
with CD and CG provides the additional phase shift necessary
to sustain oscillation. The oscillation
frequency (f0) is 50 to 250 ppm above the crystal’s series
resonant frequency (fS).
Drive Level:
RA is used to limit the crystal’s drive level by forming a voltage
divider between RA and CD. RA also stabilizes the oscillator
against changes in the amplifiers output resistance (R0). RA
should be increased for higher voltage operation.
The CX4 crystal calibration tolerance is influenced by the
effective circuit capacitances, specified as the load
capacitance (CL). CL is approximately equal to: CL = ((CD x
CG)/(CD + CG)) + CS
NOTE: CD and CG include stray layout to ground and CS is
the stray shunt capacitance between the crystal terminal. In
practice, the effective value of CL will be less than that
calculated from CD, CG and CS values because
of the effect of the amplifier output resistance. CS should be
minimized.
The oscillation frequency (f0) is approximately equal to:
f0 = fS [1+ (C1 / (2(Co + CL))]
Where fS = Series resonant frequency of the crystal
C1 = Motional Capacitance
Co = Shunt Capacitance
Please note that all data is only valid at 25°C unless otherwise
stated.
Frequency Parameters
Frequency
600.0kHz to 2.5MHz
Frequency Tolerance
±500.00ppm to ±10,000.00ppm
Tolerance Condition
@ 25°C
Ageing
±5ppm max in 1st year @ 25°C
Turning Point To²: 35°C
Temperature Coefficient: -0.035ppm/°C² typ
Note: Frequency f at temperature T is related to frequency fo
at
turning point temperature To by: ((f-fo)/fo)= k(T-To)²
Quartz Crystal Specification
CX4 EXT
Outline (mm) -SM1 = Gold Plated (lead free)
glass lid
Conventional CMOS Pierce Oscillator Circuit
Sales Office Contact Details:
UK: [phone]
Germany: 0800 1808 443
France: 0800 901 383
USA: +1.760.318.2824
Printed on 25 Apr 16 11:37 using Model Data Sheet V1.2550
Email: [e-mail]
Web: www.iqdfrequencyproducts.com
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