SOURCE: Epson Toyocom Corp.

Epson Toyocom Corp.

October 05, 2009 07:30 ET

US-Based Epson Toyocom Timing Products Division Announces Development and Availability of Ultra-Accurate, High-Stability TCXO

New TG-5500CA Provides OCXO-Class Frequency/Temperature Coefficient

EL SEGUNDO, CA--(Marketwire - October 5, 2009) - Epson Toyocom Corporation's U.S.-based Timing Products Division today announced the development of a highly accurate new TCXO (temperature-compensated crystal oscillator) that has an OCXO-class frequency/temperature coefficient of +/-0.1 x 10(-6), enabling power and space saving in telecom network equipment. Samples of the new TG-5500CA oscillator are scheduled for availability in December 2009.

Reference clocks used in ultra-compact cellular base stations for home and office use require high accuracy, with a frequency/temperature coefficient of +/-0.1 x 10(-6) or better. Core telecom network equipment, meanwhile, requires stability of +/-4.6x10(-6) over a period of 20 years. Obtaining this class of frequency tolerance/stability normally requires the use of a highly stable oscillator in the OCXO (oven-controlled crystal oscillator) or atomic oscillator classes.

The new 7.0 x 5.0 mm TG-5500CA, in addition to being equipped with a QMEMS(*1) crystal unit, has an original structural design that takes into account thermal conductivity and stabilizes the frequency/temperature coefficient and long-term aging characteristics. In addition, frequency-stability characteristics that affect the quality of transmissions, such as temperature tracking(*2) and frequency fluctuation(*3), have also been dramatically improved compared to our conventional 7.0 x 5.0 mm TCXOs (Figure 2).

This improvement enables frequency tolerance/stability that is one rank above that of current TCXOs. The TG-5500CA is now easily used in applications that were formerly reserved for OCXO-range devices. Using a TCXO instead of an OCXO can significantly help reduce the power consumption and the ultimate size of systems.

The TG-5500CA can also be used to improve the performance and function of systems that employ an existing TCXO, but it is exceptionally well-suited for use in core telecom network equipment, such as femtocell(*4) base stations and Stratum 3(*5) products.

Main Features

1)  Ultra-high stability, with a frequency/temperature coefficient
    of +/-0.1 x 10(-6)
2)  Excellent hysteresis characteristics
3)  Long-term frequency ageing characteristics (+/-3.0 x 10(-6)
    over 20 years) meet Stratum 3 requirements
4)  Good temperature tracking and minimal frequency fluctuation

Main Specifications

    Item                 Specifications                 Remarks

Output frequency        10 MHz to 40 MHz
  range             10 MHz, 13 MHz, 19.2 MHz,      Standard frequency
                         20 MHz, 26 MHz

Supply voltage              3.3 V                Supply voltage range:
                                                    2.7 V to 5.5 V
Frequency /
 temperature            +/-0.1 x 10(-6)             0 °C to +70 °C

 consumption              4 mA Max.            CMOS load (15 pF), 26 MHz

Frequency aging        +/-0.5 x 10(-6)                 First year
                       +/-3.0 x 10(-6)                  20 years

 dimensions          7.0 x 5.0 x 1.5t mm

About the Graphs

The top graphs are for Epson Toyocom's previous product (7.0 x 5.0 mm). The bottom graphs are for the new TG-5500CA. The vertical axis represents the temperature. The horizontal axis represents time. Changes in frequency as the temperature is lowered from 70 °C down to 0 °C are plotted on the graphs. The TG-5500CA exhibits smaller frequency fluctuations than the previous product. (Left) Even when the temperature slope time from 70 °C to 0 °C is reduced from 10 minutes to 5, the frequency is the same level at every temperature point, indicating stable temperature tracking. (Right)


(*1) QMEMS

QMEMS is a combination of "Quartz," a crystalline material with excellent characteristics such as excellent frequency stability and high precision, and "MEMS" (micro electro mechanical system). QMEMS devices, produced via a microfabrication process on a quartz material instead of on a semiconductor material like MEMS, offer high performance in a compact package.

QMEMS is a registered trademark of Epson Toyocom.

(*2) temperature tracking

Temperature tracking describes the characteristics of changes in frequency versus steep changes in the temperature outside a device. These characteristics are shown separately from so-called ordinary temperature characteristics, which are the characteristics of frequency changes versus small, static temperature changes over time.

(*3) frequency fluctuation

A slight, short-term variation in the frequency of an oscillator. Frequency fluctuations may be caused by factors that are independent from temperature changes, such as the Q value of the crystal unit, oscillation circuit noise, and temperature compensation circuit noise. Here, however, "frequency fluctuation" refers to slight variations in frequency resulting from temperature fluctuations caused by factors such as the flow of air or temperature changes in the vicinity of the device.

(*4) femtocell

Ultra-compact mobile phone base stations that provide coverage over an area with a radius of several dozen meters. Intended primarily for use in homes and offices, especially those in tall buildings, femtocells also target service in dead zones and, in the future, home network service.

(*5) Stratum 3

The third-highest stratum level, on a time basis, defined in a standard for digital network synchronization. Stratum 3 clocks are used in SONETs (Synchronous Optical NETworks) and NTP (Network Time Protocol: a protocol that provides accurate time information within a network) servers. A Stratum 3 oscillator requires long-term stability of +/-4.6 x 10(-6) over 20 years and short-term stability of +/-0.37 x 10(-6) over 24 hours.

About Epson Toyocom

Epson Toyocom Corporation is the global leader in crystal devices, which serve as the heart and pulse for a wide range of electronic products for consumers and industry. Utilizing its innovative hybrid quartz microfabrication technology, QMEMS, Epson Toyocom offers technological expertise in timing, sensing, and optical devices, and maintains its leadership position by providing customer-specific combinations and solutions.

About Epson Electronics America, Inc.

The Timing Products Business Unit of Epson Electronics America, Inc. (EEA) is the North American sales, marketing, and engineering arm of Epson Toyocom Corporation (Epson Toyocom) and provides a wide array of crystals, oscillators, real-time clock modules, SAW products, optical devices and gyro and pressure sensors. Based in El Segundo, California, the EEA group has more than 40 sales representative offices nationwide and a growing network of exclusive distributors. For more information, please visit and click on the Epson Toyocom center box. Both Epson Toyocom and EEA are part of the Seiko Epson Group, which consists of 108 companies around the world.

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