Timing devices are widely applied in various electronic products, which provide regular clock signals for circuits and enable coordination or synchronization among electron devices. This text will briefly introduce the categories of timing devices and the application of Murata timing devices in health care products.
High quality timing devices can satisfy high-precision medical requirements
Each kind of electronic equipment includes lots of electronic circuits. Clock signals are steady signals that conduct interval oscillation with certain regularity, which can also be explained as steady periodic oscillation and are necessary for normal operation of circuits. In other words, electronic circuits operate by referring to clock signals because they not only provide timing reminders for circuits in order to operate the function, but also enable coordination or synchronization between circuits and peripheral controllers. Reference signals produced by timing devices with constant periodic oscillation are essential for ensuring the normal functions of electronic equipment. In most timing devices, the core element is made of ceramics or crystal.
How do timing devices produce steady clock signals? The operating principle is to adopt a piezoelectric effect which means certain piezoelectric materials can respond to the charge accumulation produced in the process of applying mechanical stress. The inverse piezoelectric effect is to produce inner mechanical strain while applying electric fields on piezoelectric materials. The application of these principles in quartz crystals and ceramics can produce the oscillation with steady frequency.
By applications, categories, or functions, crystal devices can be divided into quartz crystals utilizing stable crystals to produce constant frequency oscillation and crystal oscillators with module package applied in oscillating quartz crystal circuits. With oscillating components applying the mechanical resonance principle of piezoelectric ceramics, ceramic resonators are quite beneficial to small and mass production, which can be used in a series of applications like automotive electronics, consumer equipment, and household appliances.
Resonance materials can be divided into two categories including poly-crystals (ceramics) and mono-crystals (quartz crystals). Most of the poly-crystals (ceramics) are composed by fine crystals, among which each crystal has positively or negatively charged atoms. By applying high direct current voltage, polar axes produced by spontaneous polarization can arrange themselves in a uniform direction to turn ceramics into piezoelectric ceramics with a poly-crystalline structure. Mono-crystals (quartz crystals) are piezoelectric mono-crystals, of which low-level crystal defects and impurities stand for the characteristic of high frequency temperature. The production of artificial crystals pays special attention to the quality in order to be close to the characteristic of natural crystals through minimizing the level of crystal defects and impurities.
Murata Crystal Resonators adopt a package structure that is different from common crystal resonators. Compared with common crystal resonators adopting a ceramic package with a cavity structure, Murata Crystals Resonators adopt a structure combined with aluminum oxide substrates and metal caps with a flat structure in ceramic resonators. Compared with traditional crystal resonators, they can improve the stability of supply and the corresponding ability of production increases while simultaneously reducing material costs.
In health care electronic products like glucometers and sphygmomanometers, etc., timing devices have a critical influence on measurement precision. In addition, timing devices with an exquisite volume can also shrink the product size and reduce power consumption. Taking the timing device in blood glucose machines as an example, we can see the choices of Murata’s programs. First, aiming at main processors, USB and display control units, SMD ceramic resonators are adopted in the CSTCR-G series (from 4 to 7.999 MHz) and CSTNE-G & CSTNE-V series (from 8 to 20 MHz), which achieves high density installation through small-scale package without any external load capacitor. It can also realize long-term stable supply by adopting a CERALOCK® base metal with metal electrode technology and without utilizing any precious metal (palladium).
SMD crystal units in the XRCGB-F-P series (16 MHz/24 MHz/32 MHz) adopting resin sealed packages can be used in BLE (Bluetooth Low Energy), while those in the XRCMD series (32 MHz) adopting metal sealed packages can also be used in BLE. Crystal units with the frequency of 37.4 MHz/38.4 MHz/40 MHz/48 MHz can be used in WiFi, while SMD crystal units in the XRCTD series (37.4 MHz/38.4 MHz/48MHz) adopting metal sealed packages can also be used in WiFi. XRCTD (32 MHz) crystal units can be used in BLE. These devices adopt Murata’s original packaging technology to realize these compact high quality crystal units and the load capacitor depends on the design of users who can specify the volume to reach the optimum value.
In addition, MEMS timing devices in the WMRAG series (32.768 kHz) can also be used in BLE. Murata MEMS resonators are piezoelectric components that are used as mechanical resonators to produce a constant frequency. MEMS technology is used to realize the resonators with the smallest volume in the world, with extremely low ESR characteristics, which cannot be achieved by the current quartz crystal resonators. Murata MEMS resonators adopt an ultra-compact chip scale package (CSP) that realizes excellent frequency accuracy and stable temperature characteristics without using active elements to correct the initial frequency and frequency shift caused by temperature, which is beneficial for customers to reduce power consumption and mounting space.
Piezoelectric acoustic generators in the PKLCS series (2.0 kHz/2.4 kHz/4.0 kHz) and PKMCS series (4.0 kHz) can be used in beepers. This kind of SMD piezoelectric acoustic generator conducts optimization aiming at small scale equipment like glucometers, clinic thermometers, photo flashes in cameras, and portable terminals. SMD acoustic generators used in high density installation are products developed by adopting Murata's exclusive acoustic design, structure design technology, and high performance ceramics.