Seiko Instruments Inc.

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Quartz Crystal

Quartz

Quartz

◆What is Crystal Oscillator?

A cryatal oscillator is one packaged product contained with a crystal resonator and an oscillation circuit. (No matching test needed.)
It generates stable frequency and desirable frequency accuracy by suppling power since it is already tested for matching.
Below is figure 1 for crystal oscillator’s structure.

A diagram showing the internal structure of a crystal oscillator. It illustrates a single-package solution containing both a crystal resonator and an oscillation circuit. The diagram highlights that the product is pre-tested for matching, ensuring stable frequency and high accuracy immediately upon power supply, without the need for additional matching tests by the user

We offer you two kinds of crystal oscillators as below.
・TCXO (SH-32R): has temperature compensation function with temperature sensor and memory contained.
・SPXO (SN-20S): Ultra low current consumption 0.5μA Typ. (Vdd=3.3V)
Both of them can generate 32.768kHz under low current consumption since they have quartz tuning fork crystals.
For more details, please refer to the Figure 2, 3 as below.

A technical table comparing the current consumption of two types of oscillators: TCXO (SH-32R) with temperature compensation and SPXO (SN-20S) without temperature compensation. It illustrates the difference in power requirements between the two models under a standard supply voltage
A technical table comparing the frequency tolerance of the TCXO (SH-32R) and the Crystal Resonator (SN-20S) across various temperature ranges. It demonstrates that the TCXO, equipped with a temperature compensation function, achieves superior frequency stability compared to the standard crystal resonator

◆What are the merits of crystal oscillator?

・It can supply clock to the Micro Controller Unit without an oscillation circuit.
・It can generate the desirable frequence accuracy not affected by any other components such asn external capacitor, circuit board, and load capacitance of the oscillation circuit.
【 ±3ppm (SH-32R@25℃)　±20ppm (SN-20S@25℃) 】
・It can generate the desirable frequence accuracy under the wide range of temperature. (SH-32R)
・It can be activated under ultra low current consumption. (SN-20S)
・You can save the space on the circuit board by using the oscillators.
・You don’t need to take matching test for your application.


 

A comparative diagram of circuit layouts between a Crystal Resonator (SC-20S) and a Crystal Oscillator (SN-20S) connected to an MCU. The resonator circuit requires two external capacitors (Cg/Cd). In contrast, the Crystal Oscillator circuit eliminates the need for those two capacitors and works with only one bypass capacitor. A blue callout text emphasizes that this configuration saves 30% of the oscillation circuit area with no effect on frequency tolerance
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Crystal Resonators