Application Notes
Crystal Resonators
The importance of quartz crystal resonators in electronics results from their extremely high Q, relatively small size and excellent temperature stability.
A quartz crystal resonator uses the piezoelectric properties of quartz. The direct piezoelectric effect refers to the electric polarization of certain materials brought about by the application of mechanical stress.
Timekeeping
Since its introduction the 32.768 kHz miniature watch crystal has become the most popular time keeping reference ever. This application note is intended to give some guidance as to the use of quartz crystals in time keeping applications.
In almost all circumstances designers will want to use simple logic gate oscillators for this application for the sake of convenience and cost. The criteria normally applied to this type of design are that it should be accurate, low in cost and low in power consumption. Using a watch crystal and CMOS logic all these criteria can be met.
Jitter
Measuring and specifying jitter using a phase noise plot for a crystal oscillator that contains only random jitter sources has several advantages over conventional time domain methods using high-speed digital sampling oscilloscopes (DSO’s).
The jitter performance of the oscillator is often much better than the combined jitter uncertainty of the DSO’s internal sampling oscillator, the DSO’s trigger point uncertainty and some questionable software techniques.
Specifying Quartz Crystals
Quartz crystals are the most technically simple product IQD offer, the package contains only a piece of quartz wafer, all the supporting circuitry needed to create the oscillation must be provided by the customer’s circuit. The quartz wafer inside…
Specifying Clock Oscillators
Clock oscillators are the most technically simple oscillator IQD offer, the package contains a quartz wafer and also the necessary circuit to make the quartz resonate. Consequently by applying the correct power supply to the device a stable output…
Specifying MEMS Oscillators
IntroductionMicro Electro Mechanical Systems or MEMS as it is commonly known is the latest technology to be used in the Frequency Products market as an alternative to quartz based devices.MEMS devices use a "silicon-beam" rather than quartz as the…
Specifying Fast Make Oscillators
IQD’s range of fast make oscillators are one time only factory programmable parts. As such they are available at much shorter lead times than standard fixed frequency oscillators.This can be particularly useful for developing a circuit design when…
Specifying VCXOs
Voltage Controlled Crystal Oscillators give a stable clock output waveform which can be changed via an analogue voltage input. The technology makes use of the pullability of the crystal, its change in frequency due to change in load capacitance. The…
Specifying TCXOs
Temperature Compensated Crystal Oscillators give much tighter frequency stabilities than standard clock oscillators. The frequency over temperature change of the quartz crystal is internally monitored and compensated for using a similar process to…
Specifying OCXOs
Oven Controlled Crystal Oscillators offer frequency stabilities even tighter than those offered by a TCXO. The frequency drift of the quartz crystal due to temperature shift is reduced by heating the crystal in an oven and so holding the temperature…
Frequently Asked Questions
• What is the Piezoelectric effect? Quartz crystals depend upon the piezoelectric effect in order to function. It is based upon a quartz resonator coated with an electrode on both faces then mounted in a sealed holder. Application of an external…
RoHS
IQD RoHS Policy IQD is committed to supplying products that conform to the European Union (EU) Directive 2011/65/EU: Restriction of Hazardous Substances (RoHS).According to the RoHS Directive, the following six substances should have been phased out…
Accreditations
AccreditationsISO 9001Originally obtaining certification to BS 5750 in 1988, all IQD’s design, manufacturing and test facilities are certified to ISO 9001:2008. Our quality management systems continually improve and adapt to meet the requirements…
About
IQD Frequency ProductsBacked by a pedigree that has been developed over nearly 40 years, IQD Frequency Products is a recognised market leader in the frequency control market. We have operations in America, Asia and Europe including our specialist…
Tape and Reel Details
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IQD Statek Tech Notes
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IQD FOQ GmbH
Our specialist high precision division, IQD FOQ GmbH in Germany (previously FOQ Piezo Technik), has over 30 years experience in developing high precision crystals and oscillators including specialist Clock Oscillators, VCXOs, TCXOs and OCXOs. The…
Quartz Crystals
Quartz crystals are used in a wide range of electronic applications. The High Q factor of the quartz means that tight stabilities can be achieved; this is key to ensuring microprocessor timing circuits work correctly within customer’s designs. IQD…
Crystal Clock Oscillators
Crystal Clock Oscillators are a “plug and play” quartz crystal and are used in many telecom, military, industrial and consumer applications. IQD’s comprehensive range of Crystal Clock Oscillators are available in a range of voltages down to…
MEMS Oscillators
IQD’s Micro Electro Mechanical Systems (MEMS) oscillators are a silicon based alternative to traditional quartz based oscillators. They offer low susceptibility to shock and vibration compared to quartz based products and are primarily intended…
Fast Make Programmable Oscillators
Programmable Oscillators are PLL based and are one time programmable by IQD. They provide an ideal solution where customers require a short delivery for prototyping or urgent production runs. IQD offers a comprehensive range of programmable…
Automotive Crystals & Oscillators
IQD’s comprehensive range of Automotive Crystals and Oscillators are qualified to AEC-Q200 standard and can be released to TS16949 where required. Full PPAP documentation (levels 1 to 5) is also available if requested. All types of automotive…
VCXOs
Voltage Controlled Crystal Oscillators (VCXOs) are used mainly in the telecom, test and broadcast industry. They enable customers to adjust the frequency by as much as ±150ppm while the circuit is active and so match an incoming signal. IQD’s…
TCXOs & TCVCXOs
Temperature Compensated Crystal Oscillators (TCXOs) and Temperature Compensated Voltage Controlled Crystal Oscillators (TCVCXOs) offer stabilities as tight as parts per billion (ppb). They are used where the stability of a standard Crystal Clock…
OCXOs
Oven Controlled Crystal Oscillators (OCXOs) deliver the ultimate piezo electric performance with stabilities down to less than ±1ppb. IQD’s range includes frequencies up to 100MHz with a wide choice of package sizes, supply voltages and outputs…
Jitter and Phase Noise
An Introduction to Noise and JitterA measurement of the performance of a frequency system is its stability, i.e. the level of fluctuations in frequency over a suitable measurand. The goal is to keep these fluctuations to a minimum; however noise and…
RoHS
IQD Automotive RoHS Policy IQD is committed to supplying products that conform to the European Union (EU) Directive 2011/65/EU: Restriction of Hazardous Substances (RoHS).According to the RoHS Directive, the following six substances should have been…
RoHS
IQD RoHS Policy IQD is committed to supplying products that conform to the European Union (EU) Directive 2011/65/EU: Restriction of Hazardous Substances (RoHS).According to the RoHS Directive, the following six substances should have been phased out…