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Temperature Compensated Crystal Oscillator (TCXO / VCTCXO)

TCXO

The TCXO (Temperature Compensated Crystal Oscillator) is used to create a stable frequency reference over a prescribed temperature range with a clipped sinewave output for a very low operating supply current. Pericom TCXOs support various power supply voltages, output frequencies, temperature stability and other features Pericom TCXOs compensate for variables such as ambient temperature, voltage, or load environments. Pericom TCXO has excellent phase-noise performance and is best for GPS, smart-phones and wireless-modules applications.


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TCXO / VCTCXO FAQs

How can I perform electrical testing of Pericom TCXO products?

Please refer "TEST CIRCUIT" section within Pericom datasheet.

 

How do I know if a device has been obsoleted? I am unable of find the datasheet on the Pericom website.

If the datasheet is not found on Pericom's website, it is a strong indication that the part has been obsoleted. there are several ways to find out.  The first method would be to check on the Product Detail page for your particular product choice, if there are related PDN notices, they will show up on the tab, marked "PDNS".

Alternatively go Discontinuation Notices to search for the part number.

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.

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 are typical applications of TCXO?

Typical application of TCXO include Smart-phones, PND, Tablets, Wireless modules, WiMax, LTE, Wireless Metering, Wireless Base Stations, Radio Communications, Automotive and GPS-related applications.

 

What does "TCXO" mean?

TCXO means "Temperature Compensated Crystal Oscillator" A TCXO is essentially a quartz crystal integrated with compensation electronic circuitry sensitive to temperature variation. The compensation circuitry helps TCXO maintain high frequency stability over temperature (0.5ppm - 5ppm)

 

What does "TCXO" mean?

TCXO means "Temperature Compensated Crystal Oscillator" A TCXO is essentially a quartz crystal integrated with compensation electronic circuitry sensitive to temperature variation. The compensation circuitry helps TCXO maintain high frequency stability over temperature (0.5ppm - 5ppm)

 

 

What is aging for TCXO?

The aging refers to the amount of frequency drift over an extended time period and is usually expressed in terms of ppm per year.

 

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: http://www.pericom.com/products/crystals-and-crystal-oscillators/

 

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 phase noise of TCXO?

The phase noise parameter of TCXO is a measure in the frequency domain and is specified in decibels at various offset frequencies from the carrier (-dBc/Hz).

 

What is start-up time of TCXO?

The start-up time of TCXO is defined as the time from when the power supply reaches its specified value to the time the oscillator output signal amplitude reaches 90% of its steady state voltage output logic high level.

 

 

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 the operating temperature range of TCXO products?

The operating temperature range is defined as the maximum and minimum temperatures that the TCXO can be normally operated. Over this temperature range, all of the specified operating parameters are guaranteed. Pericom TCXO offers two typical operating temperature range: -30ºC to +85ºC (Consumer grade) or -40ºC to +85ºC (Industrial grade)

 

What is VCTCXO?

VCTCXO is a TCXO component with a voltage control option. It combines the characteristics of frequency pullability of a VCXO with the temperature stability of a TCXO. Pericom offers both TCXO products (WT series) and VCTCXO products (WC series)

 

 

What kinds of TCXO package offered by Pericom?

Pericom offers two kinds of TCXO packages: TCXO 3225 (3.2 x 2.5 x 1.2 mm) and TCXO 2520 (2.5 x 2.0 x 0.8 mm)

 

What's common TCXO frequency stability over temperature?

Pericom TCXO products provide the following common frequency stability over temperature: 0.5ppm, 1.0ppm, 1.5ppm, 2.0ppm, 2.5ppm, 5.0ppm.

 

What's TCXO output logic?
What's TCXO's frequency stability over temperature?

Commodity TCXOs are available from +/-0.5ppm to +/-5ppm frequency stability over -30ºC to +85ºC (Consumer grade) or -40ºC to +85ºC (Industrial grade)

 

What's the Frequency Control Range of VCTCXO?

The frequency control range or pullability of a VCTCXO refers to the amount of frequency change (in ppm) with respect to a change in the control voltage (Vcont).

 

What's the supply voltage of TCXO?

Pericom TCXO supports the supply voltage from 1.8V to 3.3V. Common supply voltages include 1.8V, 2.5V, 2.8V, 3.0V and 3.3V.

 

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 most TCXOs are available with clipped sinewave outputs?

"1. CMOS output would add significant power dissipation to the TCXO IC. The resulting temperature gradients on the IC and in the package would limit the ability to achieve the best TCXO compensation

2. The wide range of possible CMOS loads would alter the compensation design as internal thermal gradients result in the TCXO not meeting specifications.

3. CMOS outputs result in power supply and ground transients when the output is changing levels. This noise would adversely affect the phase noise performance of the TCXO

4. CMOS outputs generate much larger EMI/RFI signals that can result in difficulties meeting the USA FCC and other countries radiated energy limits from the final system. The clipped sinewave, being both low amplitude and mostly sinusoiddal, results in low signal levels and less harmonics.

5. Many of the applications where these TCXOs are used have ASIC inputs that accept the clipped sinewave and convert to CMOS logic levels internally."