Quartz Crystal HC49SMD

1. Quartz Crystal HC49SMD (PDF: 598KB) ↓ Download

Kingtronics offers high quality SMD crystals at incredibly aggressive prices. The HC49SMD series is an industry standard crystal package. This is a low cost, low profile timing option for applications where cost is critical.

The HC49SMD is available in tight tolerances and stabilities for demanding applications. With a broad frequency range from 3.200MHz to 100.000 MHz, the HC49SMD can serve as a low cost solution in virtually any application or market.

The HC49SMD is available in surface mount (SMD) packaging only.

Quartz Crystal HC49SMD Applications

• CPU, Memory
• Computor, Printer
• Network Apapter Cards
• Remote Control Devices

Kingtronics (Kt) Quartz Crystal and Oscillator Photos

Constant Electrical Parameters of Quartz Crystals

Generally, Quartz Crystals are manufactured according to industry standard guidelines pertaining to such variables as package type, (a.) Mode of Operation, (b.) Equivalent Series Resistance, (c.) Shunt Capacitance, and (d.) Drive Level. Although these parameters may vary slightly between manufactures, and review of these parameters should be done when crossing between manufacturers, one can generally assume that these parameters will remain constant.

a. Mode of Operation (Resonance Frequency):

A Quartz Crystal has two basic modes of operation comprising Fundamental and Overtone Modes. For frequencies below 30MHz, a crystal manufacturer will use the Fundamental Mode of operation. For frequencies exceeding 30 MHz, overtone modes are recommended (overtones are not precise integer multiples of the fundamental as in a similar concept found in harmonics) Higher Fundamental mode Crystals are possible, however the crossover at 30MHz is generally considered the point where the Fundamental mode Crystal becomes more expensive to produce due to thinning of the quartz blank (increasing breakage during production). Using Overtone Modes in production therefore reduces manufacturing costs for higher frequency applications. A good rule of thumb is to assume the a Crystal manufacturer will produce a Fundamental Crystal below 30MHz, and an Overtone Crystal above 30MHz. If higher frequencies are required in the Fundamental Mode, please contact Kingtronics for support and details on Inverted Mesa technology.

b. Equivalent Series Resistance (ESR):

The Equivalent Series Resistance is the resistive element of the quartz crystal equivalent circuit. This range is normally found to be 25-100 ohms for most Quartz Crystals and is usually specified as a maximum value. Typically, these values are specified according to frequency ranges and are very similar across multiple manufactures because similar holder types, electrodes, modes of operation, and mounting structures are used in achieving specific frequencies. More significant at lower frequencies, it should be noted that ESR values at a given frequency for an AT- strip cut crystal (commonly used in Surface Mount devices) are higher than that of the standard (round blank) design (commonly found in Through Hole devices)

c. Shunt Capacitance:

The electrodes present in a Quartz Crystal, plus the stray capacitance of the holder, form a capacitance in parallel with the LC model. Generally, the Shunt Capacitance is sought to be as low as possible in manufacturing the device, as some oscillators cannot tolerate an excessive value. Because Shunt Capacitance may vary according to the size of the Crystal, manufacturers will normally designate a maximum value usually at 7.0pF. If a lower value is required, we suggest contacting technical.

d. Drive Level:

Specified by Quartz Crystal manufacturers to provide a guideline for maximum values, the Drive Level should be held to a minimum to avoid problems with Aging, Stability, nonlinear coupled modes, and other nonlinear effects. Improvements in phase noise performance can be realized with increased drive levels; however, so careful consideration should be given to this Electrical Parameter when approaching the maximum suggested level.