New Technologies Drive Crystal and Oscillator Development

摘要

The past two years have been witness to more changes in frequency control devices than in the previous 10 years combined. As more electronic handheld devices are created, the need for smaller, lower power frequency sources has grown exponentially. Mix in the demand for wireless connectivity and the need for complex networking infrastructure and the development of sophisticated high frequency, low jitter devices becomes inevitable. Moreover, these technological developments have occurred simultaneously with severe price erosion. First, let's look at the size of frequency control devices. Since the frequency of a quartz device is a direct product of its dimensional size, it is very challenging to alter the crystal's overall length and width. Just a few years ago, 7 mm X 5 mm and limited 6 mm X 3.5 mm crystals were the smallest available. Over the last two years, however, crystals in sizes of 5 mm X 3.2 mm, 4 mm X 2.5 mm, 3 mm X 2.5 mm, 2.5 mm X 2 mm and even 2 mm X 1.6 mm have been introduced with no end to the reduction in sight. One caveat to the shrinking size of the quartz crystals is that the available frequency range also shrinks since it becomes physically impossible to get a low frequency crystal in an extremely small size. An example is in a 2 mm X 1.6 mm crystal, where the lowest possible frequency is 26 MHz, versus a 7 mm X 5 mm part that can have a frequency down to 6 MHz.