Today's wireless mobile products, in addition to the increasing volume and power saving requirements, are also moving toward multi-function, multi-band, multi-system, and multi-protocol integration and integration. Such as: GSM, CDMA, WCDMA and GPS, Bluetooth, WiFi, WiMAX and other different functions combined in one product. This also poses a challenge to design and mass production. Designers should consider the maturity and sustainability of the technology when choosing a solution.
The whole machine is getting smaller and smaller, frequency resources become more and more crowded, and high-performance filters appear to be particularly important. With the rapid development of wireless communications and wireless access, frequency resources become more and more crowded, and the protection intervals between different communication system frequency bands become greater. The smaller it comes. On the one hand, this imposes more stringent requirements on the spectrum and power of the transmitting end of each system, ensuring that the transmitted signals have a high linearity and cannot increase the transmit power arbitrarily to increase the communication distance or reliability.
At the same time, the environment at the receiving end is worse, especially for smaller and smaller mobile products, the interference increases, and the improvement of receiving sensitivity and anti-interference must be enhanced. Especially in the 2.4GHz band, there are ISM, Bluetooth, WiFi, WiMAX and other protocol services. In order to ensure that each system works normally and does not affect each other, it is indispensable that each system receive front-end with high-performance filters. In this way, it can achieve small in-band insertion loss, large out-of-band attenuation, and high selectivity, and the receiver will not block the receiver channel due to adjacent band transmitters (eg, LET band 40, 2300-2400 MHz) (eg, WiFi, 2400-2482 MHz). ). It is worth pointing out that the ISM (Industrial, Scientific, Medical) use of wireless services for frequency applications is not subject to filing (filing), which further increases the unpredictability of interference sources.
The small size and high performance of the FBAR filter well meet the needs of handheld mobile devices. The main indicators of the filter are: Selectivity (Q value), insertion loss, temperature characteristics, and withstand power. The three main filters are: ceramic filters, SAW (SAW filter) and FABR. Table 1 compares the performance of the three filters:
Ceramic filter can withstand large power, good temperature characteristics, but low Q, large volume;
The SAW filter has low power, poor temperature characteristics and low Q value. The appropriate application frequency band is about 2GHz.
FBAR compared to SAW filter: Q is one order of magnitude higher, working frequency can be as high as 10GHz, temperature characteristics are good, withstand power is greater than. Insertion loss is small, product heat is less, extended battery life, anti-static level high ESD> 200V.
Avago's FBAR products, the world's leading analog and mixed-signal semiconductor company, have been widely used in mobile phone filters, duplexers, RF front-ends, and PGS receiving front-end modules, fully demonstrating that its technology and mass production are already very mature. .
AVAGO FBAR products, using microcap wafer (wafer) package, small size, distribution parameters, stable performance, cost-effective, easy to install, application prospects. AVAGO ACPF-7025, 2496 - 2690MHz, 2W bandpass filter measures 12.5x2.5x1.15 mm, which can fully meet the requirements of mobile products such as mobile phones.
Table 1: Performance comparison of AVAGO FBAR and SAW, ceramic filters Future communications handsets, data cards, wireless access WiMAX/LTE voice communications, and WiFi/Bluetooth data communications will realize coexistence and function complementarity, giving play to their respective capabilities , Do not interfere with each other.
FBAR filter fully considers the application environment FBAR's excellent filtering performance combined with microcap package, 50ohm input and output termination, provides a great choice for fast design of high-performance mobile phones and mobile devices, and Anwar's high stable quality and huge productivity. , And provide customers with strong protection.
Recently, AVAGO based on FBAR technology, for the 2.4GHz band of mobile phones and mobile wireless products, introduced WiFi/Bluetooth band-pass filter - ACPF-7024, and WiMAX band-pass filter - ACPF-7025, its performance indicators such as Table 2.
Table 2: Main performance of 2.4GHz band FBAR band-pass filter As can be seen from Table 2, ACPF-7024, 2400-2482MHz WiFi/Bluetooth band-pass filter with small insertion loss and good selectivity. There is a high out-of-band rejection of WiMAX, PCS, and LTE band7,40 in the adjacent bands. Indicators shown in Figure 1
Figure 1: ACPF-7024 Out-of-band attenuation 2350-2550 MHz
ACPF-7025, 2496 - 2690MHz WiMAX bandpass filter with low insertion loss and good selectivity. There is a high out-of-band rejection of WiFi/Bluetooth, PCS, 800MHz cells in adjacent bands. Implementing WiMAX transceivers and WiFi/Bluetooth transceivers can work simultaneously without affecting each other. Application see Figure 2
Figure 2: Typical multi-system block diagram In addition, Avago recently introduced a mini-duplexer AGPS-C001 for mobile applications, effectively separating W-CDMA/GSM transceiving signals and GPS/GNSS (Galileo) navigation signals. The sharing of an antenna between the two eliminates one antenna, which saves cost and increases design flexibility. See Figure 3.
Figure 3: AGPS-C001 Block Diagram AGPS-C001 is the masterpiece of FBAR technology: excellent isolation, low insertion loss and high selectivity, making GPS/GNSS and W-CDMA work “harmoniously†without interference from each other. And to reduce the performance of either side; Operating temperature range is wide, -30 °C - 80 °C; Volume is 2.0 x 2.0 x 0.95, less than 1mm thick, suitable for surface mount technology, indicators shown in Figure 4,5. Using this product to design a mobile phone with navigation function, the internet card becomes more convenient and the product performance is more stable. ,
Figure 4: AGPS-C001 Antenna - GPS Attenuator
Figure 5: AGPS-C001 Antenna - Mobile Phone Attenuation
For the above solutions and products, Avago's Asia Pacific largest distributor Shiqiang Telecom will be equipped with a dedicated RF technical support team to provide users with various technical support and product advisory services.