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Diodes Pericom: A product line of Diodes Incorporated

Voltage Control Crystal Oscillator (VCXO)

VCXO

Diodes Incorporated oscillators are low-jitter, tight-stability oscillator modules that combine proven quartz crystal resonator technology with Diodes Incorporated leading-edge clock IC technology.

Available with CMOS/TTL, LVPECL, or LVDS output logic, our voltage control oscillators achieve very tight overall accuracy of ±20 ppm for a variety of applications, including WiFi, WiMax, PON, and telecommunications standards such as SONET/SDH. Additionally, some oscillator products feature a voltage control function that enables in-circuit adjustment of the output frequency for use in data signal acquisition, clock retiming and jitter attenuation, or frequency synthesis.

VCXO Details

  • Diodes Incorporated has unique vertical integration with SaRonix-eCera for proprietary high-capacity automated production of ceramic-packaged oscillators
  • Output frequencies up to 670 MHz with ±20 ppm total lifetime accuracy available
  • 5 V, 3.3 V, 2.5 V, and 1.8 V products available
  • Patented XP Technology for cost-effective high-frequency, low-jitter clock circuits
  • VCXO control voltage function for synchronizing with another clock or data signal
  • Diodes Incorporated clock and VCXO IC enables shorter lead times and lower costs
  • Get proven technology fast with ASSP XO crystal oscillators

VCXO FAQs

Define Absolute Pull Range (APR)?

For VCXO and VCTCXO, the recomended method of defining pullability. The value is relative to the specified nominal frequency, net of the device's relative pull range and variations due to stability factors (such as temperature, aging, etc).

Define Relative Pull Range?

For VCXO and VCTCXO, a parameter used to define the maximum frequency pull from the actual operating frequency under a given set of operating conditions.

Define Stability?

Parameter used to define the maximum deviation of the actual frequency from the specified nominal frequency over changes in operating conditions. Oscillator stability is usually rated as inclusive of temperature, load, initial calibration, supply, and aging effects.

External links to some of the ASSPXO/VCXO datasheets are missing, where can I go to access them?

Please go to the Media & Downloads page. From there please click on the tab called "FCP Support Documents".
In that section, you should be able to access all the links related to each product, in terms of reflow, test circuits and tape and reel information. We apologize for the inconvenience.

Is there a replacement for an obsolete part?

Not all obsolete parts will have a direct replacement. However, we recommended that you contact your regional sales office.

TCXO

A temperature compensated crystal oscillator contains a sensor that adjusts the output frequency to compensate for variation due to ambient temperature effects on the crystal, used as a frequency reference that is one or two orders of magnitude more accurate than uncompensated XO. Some (V)TCXO offer a voltage control function for minor frequency tuning.

What are the causes of jitter?

Jitter can be cause by: poor decoupling to the Vcc and GND, signal source with heavy jitter, slow edge rate which will provide additional time to introduce jitter to the signal. Additional information can be found in Application Note 24: Designing for Minimal Jitter when using Clock Buffers

What are the types of jitter?

There are several types of jitter, but the main ones are: cycle-to-cycle jitter, period jitter, half period jitter, and peak-to-peak jitter. Jitter terminology can be found in AB36: Jitter Measurement Techniques at Application Brief No. 36 or Application Note No. 27.

What is cycle-to-cycle jitter?

Cycle-to-cycle jitter is the difference in the clock's period between two consecutive cycles and is expressed in units of + pico-seconds. This is because it can be either leading or lagging from the ideal output waveform.

What is FCP XO product?

FCP is Frequency Control Product. They include crystals, crystal oscillators (XO), voltage control oscillators (VCXO), and TCXO. XO has IC and crystal integrated together as a component for quality easy use in system designs. For more product information, please visit company website: https://www.diodes.com/products/connectivity-and-timing/crystal-and-crystal-oscillator/

 

What is half-period jitter?

Half-Period Jitter is the measure of maximum change in a clock's output transition from its ideal position during one-half period. It is measured as: tjit(half-period) = thalf-period n – 1/2 ƒo, where ƒo is the frequency of the input signal.

What is Jitter?

Measurement of the deviation of a clock period from its ideal position as calculated with respect to the average operating frequency under a fixed set of operating conditions.

What is PPM?

Part per million is used to measure the deviation of the output signal (+/-20 ppM = +/-0.002%).

What is the lead finish for Pericom products? What about lead-free?

All Pericom's products that are not lead-free are composed of 85% Sn and 15% Pb. For lead-free products, they are composed of 100% matte Sn. Lead-free products are marked and ordered with the letter "E" suffix at the end of the part number.

What is VCXO or VCSO?

A voltage controlled crystal (or SAW) oscillator offers a voltage control function to modulate the output signal used in phase-locked loop circuits that perform clock/data recovery, frequency translation, or clock jitter filtering.

What is XO or SO?

A crystal (or SAW) oscillator outputs a precise fixed-frequency clock signal at a specified nominal value, used for data and processor timing.

Where can I find Mean Time Before Failure (MTBF) or Failures In Time (FIT) values for Pericom products?

FIT and MTBF data can be found at Pericom's Quality webpage.

Where can I find the information on your Pb-free and "Green" packaging?

Lead (Pb)-Free and Green information can be found on individual datasheets or Pb-Free & Green Page.

Why is the marking on the FCT devices different from the datasheet?

Sometimes the speed grades and the package nomenclature for our FCT devices may be swapped around. Full explanation for nomenclature information can be found under Packaging Support Documentation.