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Tight-stability OCXOs timed for GPS systems

Posted: 12 Aug 2002 ?? ?Print Version ?Bookmark and Share

Keywords:M-Tron Ind. Inc. has entered the oven-controlled crystal-oscillator (OCXO) market with five new families of ultrastable? oven controlled crystal oscillator? mxo5030? mxo5040? mxo5019?

M-Tron Ind. Inc. has entered the oven-controlled crystal-oscillator (OCXO) market with five new families of ultrastable, tight-stability single- and double-oven OCXOs for designers of wireless basestations, GPS timing systems, Stratum 3/3E applications, and test equipment.

The MXO5030, MXO5040, MXO5019, MXO5026, and MXO5080 devices offer stabilities to 120ppb and non-standard frequencies to 100MHz in a variety of through-hole and surface-mount packages.

The MXO5030 OCXO family is designed for Stratum 3E applications that require 110ppb/day for the initial 24h of holdover. The family offers a variety of choices for temperature stability and choice of crystal type.

Touting tight stability and ultra low aging, the double-oven MXO5040 provides a holdover stability of 10.1 ppb/day for Stratum 2 applications, and offers excellent long-term aging, said the company, of <110ppb/year after 14 days of continuous operation.

The MXO5019 OCXO, in a 51.6-by-51.6-by-19.1mm package, is designed for applications such as test equipment, medical instrumentation, and wireless basestations that require tight stability and low noise. The family is available in both AT and SC versions.

For smaller packaging requirements but offering nearly the same performance as the MXO5019, M-Tron offers a "Euro-style" MXO5026 OCXO in a 36-by-27-by-20mm package.

For applications that require a surface-mountable OCXO, the MXO5080 boasts tight temperature stability, excellent long-term aging, low-power, and either an HCMOS or sine wave output.

OCXOs maintain tight stabilities over temperature by holding the resonator and oscillator circuitry at a constant elevated temperature the company said.

Another performance criterion is long-term aging, which is a key deciding factor in what type of crystal is used in the OCXO. SC-cut crystals, for example, are used in applications where 1100ppb/ year or less is required because they are stress-compensated and have a much smaller motional capacitance than comparable AT-cuts.

Physical performance is not affected by long-term aging and is not susceptible to external changes in the circuit, Thompson said.

Phase noise is a third critical requirement, Thompson said. While some applications require lower close-in noise (1Hz to 1kHz offset), the company said, others need lower noise floors (10kHz to 1MHz offset). Since SC-cuts have a much higher Q-factor than AT-cuts, SC-based OCXOs offer better noise performance from 1Hz offset to 1kHz offset.

Volume production is available. In lots of 500, pricing for the MXO5080, MXO5030, and MXO5026 families starts at $120 for common frequencies; pricing for the MXO5040 products starts at $375; and for the MXO5019, at $140. Delivery is 6 to 8 weeks (10 to 12 for custom frequencies).

EE Times





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