Glossary - alphabet order - "S"

SAW oscillator

This is a crystal oscillator that houses a SAW resonator chip and IC chip including crystal oscillation circuit in a package. Epson offers SAW oscillators under the EG series. In particular, the EG-2121 and EG-2102 have improved frequency-temperature characteristics to one-half their previous levels.

Reference: Frequency versus temperature characteristics

SIP package

Abbreviation for Single In-line Package. This type of package has leads (pins) that protrude from one side, and which are inserted into holes in the circuit board to mount the package.

SIP package

SMD package

This is a general term for any package that is mounted onto the surface of a PCB. SMD is an abbreviation for "Surface Mounted Device". This is one of the newer types of crystal device packages, which typically use ceramic or plastic as the package material.

SOJ package

Abbreviation for Small Outline J-leaded package. In this surface-mount package, the leads (pins) protrude from both sides and the lead ends are bent inward, beneath the package.

SOP package

Abbreviation for Small Outline Package. In this surface-mounted package, the leads (pins) protrude from both sides and the lead ends are bent outward.


Sealing means that the inside of crystal device container is kept airtight. In order for a crystal unit to stably maintain its characteristics for long, the crystal chip's surfaces, including any electrodes, must be protected from moisture or other impurities in the outside air. To assist in this, nitrogen gas is usually inserted into crystal containers. Sometimes, a vacuum is created in the sealed container of tuning fork crystal units to improve the oscillation efficiency. Package sealing methods have been developed, including insertion through soft wax-like material, resistance welding, molten glass welding, adhesion by resin, and other methods, depending on the package's materials, size, and features.

Shock resistance

This refers to a crystal device's resistance to shocks. This is evaluated by the amount of change in characteristics (particularly frequency variation) and damages caused by a specified impact. Quartz crystal is a hard and brittle material that fractures easily, so shock resistance is a key characteristic for crystal devices used in mobile products. In the past, an evaluation method was used whereby a certain amount of shock was applied to crystal products by shock testing equipment. Recently, the evaluation method is used wherein a crystal device fixed in a testing tool weighing 100-gram weight is repeatedly dropped from a certain height.

Shunt capacitance

Shunt capacitance is an electrostatic capacitance component that is generated between two electrodes in a crystal oscillator. It is shown as C0 in the equivalent circuit diagram at right.

Equivalent circuit diagram of crystal unit


The standby is a function which can stop operation of the oscillation circuit and output of a crystal oscillator. This is useful in eliminating power consumption.

Storage temperature

This is the temperature range for maintaining the operability and characteristics of a crystal device that is in storage (not being operated). Storing crystal devices in an environment that is outside this temperature range can cause degradation of characteristics or other damage. Degradation of characteristics can also occur if crystal devices are stored for a long time at temperatures near the upper or lower limits of this range, so Epson recommends that crystal devices be stored under normal room temperature and humidity conditions whenever possible.

Surface Acoustic Wave

See "SAW".

Reference: SAW

Surface mount

See "SMD package".

Reference: SMD package

Synthetic quartz crystal

This refers to quartz crystal that is made artificially, in contrast to naturally occurring quartz crystal. Both types of quartz crystal are used as a material for crystal devices. Whereas naturally occurring quartz crystal contains a lot of impurities and experiences a wide range of quality fluctuation, synthetic quartz crystal contains few impurities, which enables more stable crystal devices to be manufactured. A method called hydrothermal synthesis is used to grow various quartz crystals in specified sizes. The crystals are grown over a period of two months in an autoclave which maintains the processing conditions of a temperature of approximately +400 ℃ and air pressure of 1000 atmospheres.

Synthetic quartz crystal

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