VCXO Oscillators

VCXO Oscillators (Voltage controlled crystal oscillators) are used in designs that need to control the output frequency via an external digital PLL. The VCXO frequency is &147pulled&148 by the control voltage (Vc) applied. The function of this can be to maintain a fixed desired output frequency over time to counteract the ageing of the crystal that would otherwise cause a drift. The designer/engineer will need to know what the &147Pull Range&148 is for the selected VCXO.

Total Pull Range is equal frequency shift from minimum to maximum control voltage; typically 50ppm to 200ppm max.


Absolute Pull Range (APR)


Another common parameter used when specifying VCXO is &147Absolute Pull Range&148 or (APR) with VCXO’s offering ±35ppm to 50pp min.

APR is defined as the minimum pull range after taking into account other aspects that affect the frequency, such as temperature, ageing, power supply variations, and load variations.

APR = Total Pull Range minus expected changes from temperature, ageing, power supply variations, and load variations.

A designer picks an APR that is expected to cover all drifts for the life of the product.

VCXO’s designs fall into three types, those with a fundamental crystal, or a 3rd OT crystal, and those using an internal PLL to multiply the frequency and extend the output frequency.

Fundamental crystal types are limited to ∼80MHz, 3rd OT designs offer higher frequencies to ∼200MHz and the best phase noise/jitter performance. PLL types offer the broadest range of frequencies up to 2100MHz and can be utilized using programmable oscillators.


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Omschrijving Prijs Oscillator Type Output Frequency Frequency Stability Load Capacitance Output Level Minimum Operating Temperature Maximum Operating Temperature Height Dimensions Package Type
RS-stocknr. 178-2040
Fabrikantnummer315LB3I1228T
FabrikantCTS
€ 6,89
Each (On a Reel of 1000)
Aantal stuks
Clock Oscillator 122.88MHz ±50ppm - HCMOS -40°C 85°C 1.3mm 5 x 3.2 x 1.3mm SMD
RS-stocknr. 179-0024
Fabrikantnummer347LB3I1536T
FabrikantCTS
€ 7,64
Each (On a Reel of 1000)
Aantal stuks
VCXO 153.6MHz ±50ppm - LVPECL -40°C 85°C 1.7mm 7 x 5 x 1.7mm SMD
RS-stocknr. 671-5789
FabrikantnummerLFVCXO026156
FabrikantIQD
€ 3,84
Each
Aantal stuks
- 20MHz ±100ppm 15pF HCMOS 0°C 70°C 1.7mm 7 x 5 x 1.7mm SMD
RS-stocknr. 179-0821
Fabrikantnummer347LB3I1536T
FabrikantCTS
€ 17,38
Each
Aantal stuks
VCXO 153.6MHz ±50ppm - LVPECL -40°C 85°C 1.7mm 7 x 5 x 1.7mm SMD
RS-stocknr. 905-5850
FabrikantnummerCVHD-950-100
FabrikantCrystek
€ 17,82
Each
Aantal stuks
VCXO 100MHz ±20ppm - CMOS 0°C 70°C 5.3mm 14.2 x 9.14 x 5.3mm SMD
RS-stocknr. 178-2696
Fabrikantnummer315LB3I1228T
FabrikantCTS
€ 9,50
Each
Aantal stuks
VCXO 122.88MHz ±50ppm - HCMOS -40°C 85°C 1.3mm 5 x 3.2 x 1.3mm SMD