彼得曼32.768K有源晶振的優勢，Time requirements in modern metering applications have massively increased in the last few years. The usual requirement in modern metering applications is a time offset of 1 hour after 7 years. It should also be possible for the operating temperature range of the application to comply with this value. 1 hour max. after 7 years corresponds to a frequency tolerance of ±16 ppm absolute at 32,768 kHz. It is no longer possible for conventional 32,768 kHz oscillating crystals to meet these requirements.
On the one hand, this is because 32,768 kHz are only available with a frequency tolerance of ±10ppm at +25°C, on the other hand, the temperature stability over a temperature range of -40/+85°C is more then -180 ppm. Moreover, ageing of approx. ±30 ppm after 10 years must be taken into account when calculating accuracy. In the worst case, a 32,768 kHz crystal has a maximum frequency stability of +40/-220 ppm (including adjustment at +25°C, temperature stability and ageing after 10 years). External circuit capacitance must be able to compensate any systematic frequency offset caused by the internal capacitance of the oscillator stage of the IC to be synchronised and by stray capacitance. The selection of a layout without external circuit capacitance for the 32,768 crystal involves a great risk because the accuracy of the 32,768 crystal can neither be corrected nor adjusted to suddenly changing PCB conditions during series production. Initially, the intersection angle for the 32,768 crystal was designed for optimal accuracy in wristwatches, and not for most of the applications for which it is used nowadays.
In order to meet the highly accurate time requirements, we as a clocking specialist offer the series ULPPO ultra low power 32,768 kHz oscillator. This oscillator can be operated with each voltage within a VDD range of 1.5 to 3.63 VDC. The specified current consumption is 0.99 µA. The temperature stability of ULPPOs is ±5 ppm over a temperature range of -40/+85°C. Frequency stability (delivery accuracy plus temperature stability) is ±10 ppm, and ageing after 20 years is ±2 ppm. Thus the maximum overall stability of ULPPOs is ±12 ppm including the ageing after 10 years. These are industry best parameters.
No external circuit capacitance is required for the circuiting of the ultra small housing (housing area: 1.2 mm2). The input stage of the IC installed in the ULPPO independently filters the supply voltage. Compared to crystals, ULPPOs save a lot of space on the printed circuit board so that the packing density can be increased, and smaller printed circuit boards can be designed. The adjustment of the amplitude further reduces the power consumption of the ULPPO.
For space calculations, both external circuit capacitances for a crystal on the printed circuit board must also be taken into account. With its two external circuit capacitances, even the smallest 32,768 kHz crystal requires more space on the PCB than ULPPOs do.
Moreover, very small 32,768 kHz crystals have very high resistances which usually cannot be safely overcome by the oscillator stages to be synchronised because the oscillator stages of the ICs or RTCs to be synchronised have very high tolerances as well. Therefore, sudden response time problems in the field might occur which can be ruled out with ULPPOs. Thus, the safe operation of the application is possible with ULPPOs under all circumstances.
Oscillator stages consume a lot of energy to keep a 32,768 crystal oscillating. Usually, the input stage of the MCU can be directly circuited with the LVCMOS signal of the ULPPO (usually Xin). Thus the input stage of the MCU can be deactivated (bypass function) so that the energy saved can be used for the calculation of the system power consumption of the meter. Moreover, ULPPOs are able to synchronise several ICs at a time. Due to the very high accuracy of the ULPPO, less time synchronisations are required, which also saves system power.
Of course, ULPPOs can be used in any applications which require miniaturised ultra low power 32,768 kHz oscillators such as smartphones, tablets, GPS, fitness watches, health and wellness applications, wireless keyboards, timing systems, timing applications, wearables, IoT, home automation, etc. Due to the high degree of accuracy of 32,768 kHz oscillators, the standby time or even the hypernation time in hypernation technology applications can be significantly increased so that a high amount of system power can be saved due to the significantly lower battery-intensive synchronisation cycles. Thus the 32,768 kHz oscillator is the better choice compared to 32,768 kHz crystals. Ultra low power 32,768 kHz oscillators are available with diverse accuracy variations – see also the ULPO-RB1 and -RB2 series.
不斷精進自我的優質制造商彼得曼公司，致力于開發大量高質量的產品，隨著近幾年來，現代計量應用的時間要求大幅提高。現代計量應用的通常要求是7年后時間偏移1小時。應用的工作溫度范圍也應符合該值。最多1小時。7年后對應于32，768kHz下16ppm絕對值的頻率容差。傳統的32，768 kHz振蕩晶體不再可能滿足這些要求。彼得曼32.768K有源晶振的優勢.
一方面，這是因為32，768kHz僅在+25°C時具有10ppm的頻率容差，另一方面，在-40/+85°C溫度范圍內的溫度穩定性高于-180ppm。此外，老化約。計算精度時，必須考慮10年后的30ppm。最差情況下，32.768K有源晶振的最大頻率穩定性為+40/-220 ppm(包括+25°C時的調整、溫度穩定性和10年后的老化)。外部電路電容必須能夠補償由要同步的ic振蕩器級的內部電容和雜散電容引起的任何系統頻率偏移。為32，768晶振選擇無外部電路電容的布局包含很大的風險，因為在批量生產期間，32，768晶振的精度既不能校正也不能調整以適應突然變化的PCB條件。最初，32，768英寸晶體的交叉角度是為手表的最佳精度而設計的，而不是為如今使用它的大多數應用而設計的。
石英晶體諧振器是時鐘發生器最受歡迎的反射器.它們干凈的信號和廉價的制造證明它們的使用是合理的,即使這意味著印刷電路板中有額外的元件.隨著最近更精確的封裝制造技術,將晶體和有源電路管芯包含在同一封裝中已經變得可行.對于Si5332嵌入式晶體選項,封裝中包含外部供應商提供的高性能晶體.這帶來了許多優勢,例如縮短從晶體到時鐘發生器芯片的參考輸入路徑,以及減小解決方案的尺寸.嵌入式晶體時鐘發生器方法的實際意義,以及它如何促進時鐘樹的開發,將在以下章節中進行描述.
微信號
公眾號
