Rancho Santa Margarita, CA (PRWEB) April 30, 2014
Historically, reference oscillators used to clock a phase lock loop (PLL) circuit or provide a reference signal to any timing related circuit have predominantly utilized quartz crystals as the core resonators. The degree of difficulty associated with reducing the form factor of these devices, while controlling costs has been challenging. Furthermore, for wider temperature range solutions requiring tighter stabilities, crystal oscillators still tend to cost more than what the market is willing to bear. The newest generation of MEMS oscillators effectively addresses both challenges.
Microelectromechanical System (MEMS) based devices were first manufactured in the mid-1960s. Since then, technology has evolved to the point that it is now possible to offer temperature stabilized MEMS oscillators in extremely small form factors.
Modern day MEMS oscillators are constructed utilizing silicon wafer processing techniques. Significant advances in the creation of miniature MEMS resonator structures have enabled the manufacturing of accurate clock oscillators. These devices are now readily available through Abracon in standard oscillator footprints including: 5.0x7.0mm, 5.0x3.2mm, 2.5x2.0mm and are now compatible to a 1.6x1.2mm footprint.
Advanced circuit topologies are employed to offer both CMOS, as well as differential clock outputs, both LVDS and LVPECL. Additionally, these devices are optimized for low voltage operation, down to +1.8V standard logic levels.
A simplified block diagram of a LVCMOS MEMS oscillator is shown in Figure (1). This architecture has been successfully implemented in a ball grid array package, measuring a mere 1.792x1.252x0.680mm.
The latest MEMS oscillator offering shown in Figure (2) is designed to fit the industry standard oscillator footprint of 1.6x1.2x1.0mm. Utilizing proprietary resonator technology, this device is available in mass volume with the following key attributes:
- An available resonant frequency range of 1.00MHz to 156.25MHz.
- A bias voltage range of +1.70V to +3.60V.
- An operating temperature range (OTR) of -40ºC to +105ºC.
- An available frequency stability over OTR of ±10.0ppm with an optional ±25.0ppm and ±50.0ppm.
- A typical period jitter (rms) of 6.0ps, with a maximum of 7.0ps.
- A typical cycle-cycle jitter (rms) of 11.0ps, with a maximum of 12.0ps.
- A current drain of 9.6mA at 156.25MHz with Vdd of +3.6V or 6.9mA at 156.25MHz with Vdd of +1.7V.
The ASCSM family of MEMS oscillators, depicted in Figure (3), is configured to address any frequency need between 1.00MHz and 156.25MHz. Since these devices are factory configurable, customers can choose any desired frequency, and it can be produced immediately. Due to the standard wafer processing techniques, high volume demand can be fulfilled in a matter of weeks, rather than months, generally associated with crystal oscillators at non-standard frequencies.
This advanced series of MEMS oscillator employs a traditional fractional synthesis approach, coupled with a temperature correction circuitry. This technique enables the availability of ±10.0ppm temperature stability over a wide operating temperature range of -40ºC to +105ºC. Figure (4) depicts the typical temperature error for Abracon’s ASCSM series of MEMS oscillators.
In summary, the MEMS oscillators have evolved to provide low cost, quick turn, reference clock solutions, generally available from 1MHz to 460MHz with either LVCMOS or LVDS/LVPECL outputs. Abracon’s miniature ASCSM series was originally launched in 2013 and is being relaunched in June 2014 with the incorporation of enhanced production processes, which further reduce manufacturing costs. The ASCSM devices with an LVCMOS output from 1MHz to 156.25MHz will be available through Abracon beginning in June 2014.
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Abracon Corporation was established in 1992 with the vision of becoming a top tier global manufacturer of Frequency Control, Signal Conditioning, Clock Distribution and Magnetic Components with local design and technical support. Abracon provides its customers with high quality products, competitive pricing, timely delivery, reliable engineering and technical support, plus production flexibility worldwide.