The global market for crystals, oscillators and timing products is extremely de-fragmented and amounts to around six billion US dollars. There are many suppliers and a wide variety of solutions. This report provides information on the inexpensive trend products and can serve as a guide for new developments.
The smart clocking market is divided into three sub-segments: about 1/3 is covered by the quartz market, about 1/3 by the oscillator market (clock oscillators) and about 1/3 by the timing market (e.g. 32.768 kHz, TCxOs, OCxOs, differential). For more than 20 years now, Petermann-Technik (proper spelling: PETERMANN-TECHNIK) has been active on the market as a highly specialised partner for frequency-determining components and, in addition to a broad and deep product portfolio, offers a comprehensive design-in service with the aim of offering the customer everything from a single source and enabling a very fast time-to-market.
[caption id="attachment_315" align="alignright" width="300"] Image 1: Petermann-Technik offers a comprehensive range of "Frequency Controlled Products" in combination with engineering and logistics services[/caption] .
In recent years, there has been a major shift from large THT and SMD crystals available in metal housings (HC-49/U, HC-49/US, HC-49/US-SMD series) to miniaturised SMD crystals in ceramic housings. The demand for higher-frequency oscillating crystals in smaller housings has further fuelled this trend. Currently, the SMD crystal in a 3.2 mm x 2.5 mm/4-pad ceramic housing (SMD03025/4 series), which is available in the frequency range from 8.0 to 64.0 MHz (AT fundamental), is the most sought-after and cheapest miniaturised SMD crystal of all. With the SMD03025/4 series, Petermann-Technik offers appropriate solutions for every application (Fig. 2). These resistance-optimised crystals offer optimum transient response in the defined operating temperature ranges and can be supplied with a drive level of up to 500 µW (in the frequency range from 12 to 64 MHz) on request.
Solutions are available in the temperature range up to -55 to +125 °C. Quartz crystals cannot normally be processed ultrasonically. Another speciality in the product range of 3.2 mm x 2.5 mm/4-pad SMD crystals are the 3.2 mm x 2.5 mm/4-pad crystals of the SMD03025/4US series, which have been specially developed for ultrasonic welding.
[caption id="attachment_417" align="alignright" width="300"] Image 2: Price reductions for SMD crystals in ceramic housings have forced the switch from large THT and SMD crystals housed in metal. The 3.2 mm × 2.5 mm quartz, SMD03025/4 series, is the only quartz worldwide that can be used in end products that are ultrasonically sealed[/caption].
In recent years, the 2.5 mm x 2.0 mm/4-pad package has developed in parallel to the SMD03025/4, but has never really caught on. Those who find the 3.2 mm x 2.5 mm/4-pad housing too large can fall back on the 2.0 mm x 1.6 mm/4-pad housing of the SMD02016/4 series. The 2.0 mm x 1.6 mm/4-pad housing can be seen as the new trend housing for very small applications and is in increasing demand, with the result that prices for crystals in this housing have already fallen. Even in the 2.0 mm x 1.6 mm/4-pad housing, the resistance-optimised crystal designs are designed for optimum transient response. The developer can choose from versions with a drive level of up to 400 µW.
For 32.768 kHz crystals, smaller and smaller housings are also in demand (Fig. 3). The smallest version with dimensions of 1.2 mm x 1.0 mm is about to be launched on the market. There is now also strong demand for 32.768 kHz crystals in 3.2 mm x 1.5 mm housings (M3215 series) and 2.0 mm x 1.2 mm (M2012 series) with reduced resistance . Low resistance 32.768 kHz crystals, as well as the standard versions, are available with load capacities from 4 to 12.5 pF in the temperature range from -40 to +125 °C. Many versions can be supplied from stock or within short delivery times. The developer can choose between two frequency tolerances at +25 °C: ±10 ppm (optional) or ±20 ppm (standard).
The oscillator product range is also booming at Petermann-Technik, especially the silicon oscillator range. Developers are increasingly demanding very small, extremely durable and high-precision solutions in ever higher temperature ranges. Quartz crystals can no longer fulfil these requirements for technological reasons. Two external capacitors are needed to connect the quartz, which require space on the PCB. On the other hand, the resistance increases with ever smaller housings, which reduces the settling time. In addition, the smallest frequency tolerance for MHz crystals is +25 °C ±10 ppm, and the temperature stabilities are ±10 ppm at -20 to +70 °C, ±15 ppm at -40 to +85 °C, ±30 ppm at -40 to +105 °C and ±50 ppm at -40 to +125 °C. Depending on the version, the maximum quartz ageing is ±10 ppm after ten years. A standard silicon clock oscillator available from stock in a 2.0 mm × 1.6 mm/4-pad housing, for example, has a frequency stability of ±20 ppm at -40 to +85 °C (this includes the frequency tolerance at +25 °C, the temperature stability above -40 to +85 °C, the ageing after the first year and frequency changes caused byVDDand load tolerances) with an ageing of ±3 ppm after ten years.
[caption id="attachment_433" align="alignright" width="300"] Image 3: 32,768 kHz crystals are available from stock in a wide variety of housings, including low resistance versions for industrial and automotive applications[/caption] .
Dedicated standard silicon oscillator versions are available from ±10 ppm at -40 to +85 °C, or ±20 ppm at -55 to +125 °C with very low jitter. Oscillators can also drive loads of up to 15 pF, so that one oscillator can simultaneously clock several ICs with the same frequency (Fig. 4).
In addition to the quartz oscillators(xO, TCxO, VC-TCxO, VCxO, OCxO), the portfolio also includes silicon oscillators. Silicon oscillators are semiconductors and use a micro-silicon resonator with very low
low oscillation energy for clock generation. As a result, and based on analogue CMOS IC technology, not only can very small versions be produced, but the performance of these low-cost silicon oscillators is also very good. The MTBF is 1140 million hours (FIT 0.88) and is the best in the industry. Compared to quartz oscillators, the silicon oscillators are 30 times less sensitive to shock and vibration and 54 times less sensitive to external electromagnetic fields.
[caption id="attachment_434" align="alignright" width="300"] Image 4: Every possible quartz oscillator is included in the Petermann-Technik product range[/caption] .
In addition, ageing is ten times lower. Depending on the design, the silicon oscillators can be powered by a button cell for ten years, for example. The innovative silicon oscillators are smart clocking devices and pin-to-pin compatible with quartz and MEMS oscillators.
For new developments and as a replacement for quartz and MEMS oscillators, SMD silicon oscillators are the best and most durable choice. The specialists at Petermann-Technik can also show how multiple costs can be saved by dimensioning the oscillator accordingly. The silicon oscillator product range includes ultra-low-power oscillators (kHz + MHz), low-power clock oscillators, ultra-performance oscillators, differential oscillators, spread spectrum oscillators, TC and VCTCxO, high-temperature oscillators (versions of up to +155 °C are currently being tested), high-precision oscillators (Splendid series) and automotive oscillators (AECQ100).
LOW-POWER SILICON CLOCK OSCILLATORS
The low-power silicon oscillators sub-segment includes jitter-optimised versions in the frequency range from 1.0 to 137.0 MHz with temperature stabilities of ±20 ppm at -40 to +85 °C (LPO series), from ±20 ppm, -40 to +105 °C up to -55 to +125 °C (HTLPO series) and AEC100 automotive oscillators from the LPO-AUT (-40 to +85 °C) and HTLPO-AUT (-40 to +105 °C and -55 to 125 °C) series. The MTBF is 1140 million hours. The innovative CMOS IC technology of these oscillators makes it possible, for example, to significantly improve the EMC behaviour of the corresponding versions via the so-called soft level function. With an extension of the rise/fall time by up to 45 per cent, the EMC attenuation at the 11th harmonic is over -60 dB. An enormous value for such a simple adjustment oftrise and tfall that is free of charge for the customer.
[caption id="attachment_435" align="alignright" width="300"] Image 5: Semiconductor-based silicon oscillators are very inexpensive, variable and extremely durable. They are replacing quartz crystals and quartz oscillators in more and more applications[/caption].
Although the low-power silicon oscillators are available in various standard housings ranging from 2.0 × 1.6 mm to 7.0 × 5.0 mm, the corresponding oscillator version in a 2.0 mm × 1.6 mm or maximum 2.5 mm × 2.0 mm housing is offered to the application designer for new developments, with the very wide supply voltage range of 2.25 to 3.63 VDC (-xx- in the article designation), the frequency stability of ±20 ppm at -40 to +85 °C, ±30 ppm at -40 to +105 °C, ±30 ppm at -40/+125 °C and ±50 ppm at -55 to +125 °C, with its desired frequency. The function of pin 1 is stand-by. Even if the stand-by function is not absolutely necessary. The reason: The wiring effort of pin 1 is very low in relation to the possible price saving. Normally, stock quantities with the stand-by function are available in large quantities, so that they can be supplied at very short notice and at a favourable price. Oscillators without the stand-by function on pin 1 are usually manufactured to order in the required quantity, which is normally significantly more expensive. If no stock quantities of the desired oscillator are available, the standard delivery time, even for customised products, is four to a maximum of six weeks (Fig. 5).
ULTRA-PERFORMANCE SILICON OSCILLATORS
The ultra-performance oscillators available in the frequency range from 1.0 to 220 MHz also have the soft level function already described. The CMOS ICs enable a reduced jitter of 0.5 ps in the integration bandwidth of 12 kHz to 20 MHz, so that these oscillators can be used in all jitter-critical applications. The ultra-performance silicon oscillators are available with frequency stabilities of up to ±10 ppm at -40 to +85 °C. Ageing is ±5 ppm after ten years.
DIFFERENTIAL SILICON OSCILLATORS
Typically, differential oscillators available in the frequency range from 1.0 to 725 MHz are no longer used exclusively in telecoms, networking, video, storage and server applications, but are also increasingly being used in automotive applications (AECQ100). The differential oscillators offer LVPEC, LVDS or HCSL output signals with a typical jitter of 0.23 ps (156.25 MHz at 12 kHz - 20 MHz). Frequency stabilities are available from ±10 ppm at -40 to +85 °C, or from ±25 ppm at -40 to +105 °C for automotive versions. Differential silicon oscillators are available in standard six-pin packages with dimensions of 3.2 × 2.5 mm, 5.0 × 3.2 mm and 7.0 × 5.0 mm, with supply voltages ranging from 2.25 to 3.63 VDC.
TCXOS AND VC-TCXOS
If the developer does not require extremely large frequency control voltage ranges of up to 1600 ppm, then the crystal-based TCxOs and VC-TCxOs in the frequency range from 9.6 to 60 MHz are still the best and most favourable choice. Available in ceramic housings with dimensions of 3.2 mm × 2.0 mm, 2.5 mm × 2.0 mm, 2.0 mm × 1.6 mm or even 1.6 mm × 12 mm, these high-precision oscillators have a standard temperature stability of ±0.5 ppm at -40 to +85 °C and an ageing of ±1.0 ppm after the first year. The supply voltage range is 1.6 to 3.63 VDC. The 2.5 mm × 2.0 mm ceramic package is the most favourable and is recommended for use in new developments unless a smaller package is required.
32.768 KHZ ULTRA-LOW POWER OSCILLATORS
Energy-saving and very fast data communication or positioning after sleep mode is only possible with a highly accurate and fast 32.768 kHz system clock. With a 32.768 kHz silicon oscillator, a battery-operated solution based on hibernation technology can save over 50 per cent power. A button cell, for example, can supply an application operated with a 32.768 kHz ultra-low-power oscillator with energy for up to ten years.
Many end products utilise hibernation technology, including wearables, Bluetooth Low Energy (BLE) communication units for commercial, industrial and automotive applications, IoT applications, GPS (commercial and automotive), M2M communication, personal trackers and medical patient monitoring systems, smart metering, home automation, wireless and so on. Most energy is consumed in such applications by the power-intensive synchronisation mode, which very often has to be performed within defined time windows. In such applications, two 32.768 kHz crystals are normally used to clock the RTC of the BLE chip and a µC in addition to a high-precision MHz crystal for the radio. Due to its technology, a 32.768 kHz crystal has very poor temperature behaviour and the frequency is immediately distorted by stray capacitance or changing capacitance ratios in the circuit, meaning that the frequency drift of a 32.768 kHz is very high. This means that synchronisation must be carried out very often, which consumes a lot of power.
By using ultra-low power 32.768 kHz oscillators (ULPO-RB1, ULPO-RB2 and ULPPO series), this is no longer the case, as the 32.768 kHz ultra-low power oscillators, which are available from a temperature stability of ±5 ppm in the range -40 to +85 °C, enable the application to be synchronised much less often (significant extension of the hybernation time), which saves over 50 percent of the system energy. The board can also be reduced in size, as a 1.5 mm × 0.8 mm 32.768 kHz oscillator can tackle the RTC and the µC simultaneously and is 85 per cent smaller compared to a 2.0 mm × 1.2 mm 32.768 kHz crystal with external circuit capacitances.
The 32.768 kHz ultra-low power oscillators available inthe VDD range from 1.5 to 3.63 VDC have a current consumption of less than 1 µA, depending on the version, and also enable very fast and reliable oscillation of the ICs to be clocked.
Further information can be found at:
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SMD & THT quartz crystals, oscillators and timing products
Technical questions:
Phone: 0 81 91 / 30 53 95
E-mail: info@petermann-technik.de
