CX1-EXT Datasheet, PDF (1/3 Pages) IQD Frequency Products Ltd – Quartz Crystal Specification

ISSUE 1; January 2016
Description
The CX1 EXT surface-mount quartz crystal is hermetically
sealed in a rugged ceramic package. This crystal is
manufactured using a photolithographic process developed by
Statek and has been designed utilising the experience
acquired by producing millions of crystals for industrial,
commercial, military and medical applications.
-C SM1 Gold Plated (lead free) with ceramic lid
-C SM4 Solder Plated (lead free) with ceramic lid
-C SM5 Solder Dipped (lead free) with ceramic lid
-SM1 Gold Plated (lead free) glass lid
-SM4 Solder Plated (lead free) glass lid
-SM5 Solder Dipped (lead free) glass lid
FEATURES:
Extensional mode
Ideal for use with microprocessors
Designed for low power applications
Compatible with hybrid or PC board packaging
Low ageing
Full military testing available
Ideal for battery operated applications
TYPICAL APPLICATION FOR A PIERCE OSCILLATOR:
The low profile CX miniature surface-mount crystal is ideal for
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 CMOS Pierce oscillator circuit is shown. 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 15 to
250ppm 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.
Load Capacitance:
The CX crystal frequency 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 minimised.
The oscillation frequency (f0) is approximately equal to:
f0 = fS [1+ ((C1/(2*(C0+CL))]
Where fS = Series resonant frequency of the crystal
C1 = Motional Capacitance
C0 = Shunt Capacitance
Please note that all data is only valid at 25°C unless otherwise
stated.
Quartz Crystal Specification
CX1 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 12:01 using Model Data Sheet V1.2550
Email: [e-mail]
Web: www.iqdfrequencyproducts.com
Page 1 of 3