Step -by- step integration (integraTIon-by-parts) is a concept that has been studied since the first year of college. RF IC manufacturers are now applying this traditional method to the integration of RF wireless circuits. Pioneers in wireless ICs such as Analog Devices , RF Micro Devices, and Maxim continue to design and build new building blocks (ICs) and then create customized versions for specific customers or applications. These specialized devices were subsequently included in the standard product catalog. The products in these catalogs themselves become building blocks for more complex and complex products. Digital IC vendors have been applying this model since the 1960s . RFIC semiconductor manufacturers also adopted this model in the 1990s , which led to the birth of a large number of RFIC companies and solutions.
Step-by-step integration actually means that the design cycle only needs to start with existing building blocks, create different versions, and then combine these building blocks into more integrated circuits. The first wave of RF IC vendors successfully validated this business model.
The RFIC company has just developed and soon ushered in the .com era. At the time, it was relatively easy to raise funds (of course, today's standards ) , and fabless semiconductor companies became the preferred business model. Driven by university research support and the rapidly emerging standards of Bluetooth, 802.11x, and OC-48/192 , these companies are often pursuing highly integrated communications products such as RF or optical transceivers ( Figure 1) . Such companies do not have a step-by-step integration strategy. Instead, they usually focus on a unique application, and the goal is to make the company publicly publicly available or acquired. Although this approach was initially successful, several factors combined have limited its further development, including the bursting of the .com bubble, the economic downturn and the long recession, and the traditional value of investment has been re-emphasized. After all, the bottom line of the business is the most important. With the increase in integration and increasing competition around the world, the profits of RF ICs supporting Bluetooth and 802.11 standards have become very thin. This is because everyone is competing for limited RF IC chips in mobile phones ( Figure 2) . Due to the current overcapacity, we can imagine that this situation is difficult to change at a time, so the price of these chipsets will be very cheap.
A large number of new businesses are flooding into limited markets such as Bluetooth or 802.11 . This makes the business model that originally won by technical advantage can only maintain the advantage of about 6 months ( average cycle of hardware update ) , and will soon be surpassed by other companies. Too many superficial successes and low entry barriers quickly lead to excess production ( supply ) capacity. These companies ultimately have to make money by selling products, but their products are extremely thin when they are sold in the consumer electronics market. In other words, this RFIC integrated business model has nearly collapsed. In addition, the global nature of the consumer electronics market makes it impossible to support only a successful business with knowledge of IC design. Intersil 's sale of its wireless LAN (WLAN) business, which has a major share of the market, is a shocking event. This incident once again illustrates the difficulty of making money in the consumer electronics arena.
Peregrine initially tried to capture the trend of .com development, but Peregrine insisted on using the traditional approach to develop the company's product line: a step-by-step integrated business model from the previous generation. However, Peregrine 's approach is still different from tradition. Instead of starting its integration work from the baseband side of the RF unit, Peregrine starts with the antenna side and first integrates functions that were previously dominated by gallium arsenide (GaAs) technology.
integrated
Integration offers many benefits, such as reduced cost, reduced size, improved performance, reduced component count, and associated vendor management issues, while adding features. In the 1980s and 1990s , digital circuits evolved from large-scale integration (LSI) to very large-scale integration (VLSI) , integrating functions originally performed by discrete chips into monolithic devices. Technological advances, design tools, and the development of high-volume markets are the main drivers. RF integration is still in its early stages, mainly because HDL methods for RF IC design have not yet been developed .
Despite this, RF IC integration has achieved outstanding results. In the past decade, the RF field has made great strides, from traditional heterodyne high intermediate frequency (IF) and dual conversion receivers to low IF receivers to direct conversion reception. Similarly, the demodulation process began to use digital technology, using IF sampling and multi-channel receiver technology. The transmitter evolves from a voltage-controlled oscillator (VCO) direct analog modulation to bias in-phase and quadrature (IQ) modulation to direct transmit IQ modulation. The new polarization modulation technology is becoming a general-purpose emission structure.
Many improvements in RF structure have existed for decades, but manufacturing process technology cannot support these methods. It seems that the changes have come out in the past few years, but the research has actually been going on for many years. It's just that the advanced silicon manufacturing process has been used for quite a long time.
Barriers to integration
The integration of mobile transceivers uses a variety of possible technologies. In fact, the RF front end of the mobile phone is still in a state of technical separation. This is mainly due to power amplifiers and associated control circuits, switches, anti-static (ESD) protection, and filters. One of the research focuses on the use of silicon technology to implement power amplifiers, whether silicon germanium (SiGe) , bipolar complementary metal oxide semiconductor (BiCMOS) or Bulk CMOS technology. Now, there is no problem in doing this, but it does not match the performance of the III-V compound semiconductor. The main problem is to reduce costs.
Once this circuit design barrier is overcome and the power amplifier (PA) is implemented using silicon processes with reasonable efficiency , then another technical barrier must be faced. That is the isolation problem. Difficult to ensure that spurious signals do not transceiver coupled to the PA output and a transmitter radio frequency multiplexing structures (e.g., code division multiple access (CDMA) system) in the output signal. The limitations of isolation prevent further integration.
So why not place the RF part on the baseband chip? This is because it is difficult to ensure that the digital circuit does not affect the operation of the RF function. Peregrine 's silicon-on-sapphire RF CMOS technology has no isolation limitations between conductive and semiconductor substrates that are faced by other silicon process technologies.
Gallium arsenide (GaAs) does work on semi-insulating substrates, but lacks the complementary components needed to achieve the level of integration of silicon processes. Although GaAs has been used in many areas of RF and optoelectronics, it is now only used in high-performance front-end devices that silicon-based solutions cannot. However, even this last position of GaAs seems to be unstoppable. GaAs is rapidly fading out. Due to the lack of complementary devices, the potential for GaAs integration is limited, which is why it is bearish for its future development. GaAs is also dominant in the microwave band, but similarly, silicon technology has made great progress in this regard. In mobile phones, GaAs is commonly used in power amplifiers and antenna switches. This situation is changing.
Peregrine 's RF CMOS devices
Peregrine 's standard devices are building blocks that are manufactured in a step-by-step fashion. These devices compete directly with industry silicon and III-V semiconductor devices. In terms of switches, Peregrine 's devices compete directly with cell phone antenna switches, although GaAs devices start at least 10 years. Peregrine also manufactures high isolation switches for the cable television (CATV) market. A single-chip switch such as the PE4256 can replace mechanical relays in CATV applications, enabling the deployment of remotely addressable CATV transmission systems and reducing the number of service maintenance personnel.
The cores of these switches are also available for 5- and 6 -bit digital step attenuators with integrated serial and parallel interfaces . An additional benefit of Peregrine 's RF CMOS process is the ability to preset the power-up attenuation settings so that the device can be placed in a predetermined, deterministic state before the microprocessor gains control of the device.
Market demand for integration
Peregrine has developed a series of single-pole multi-throw cell phone antenna switches that can achieve a 10W compression point using the RF CMOS process . Unlike GaAs , Peregrine can integrate CMOS control logic. Peregrine also offers better ESD performance without the need to use a capacitor array to raise the switch to positive control logic. Until now, GaAs amorphous high electron mobility transistors (pHEMT) and PIN diodes are the only technologies on the market that meet performance requirements. Bipolar devices cannot make switches, while Bulk CMOS devices have problems with substrate insertion loss and power requirements. For low insertion loss switches, low on-resistance is a must. The simple equation below relates the insertion loss to the series resistance value.
IL = -10*log((4Rl^2/(Rs+Rl)^2)
An important parameter for switching devices is the Ron*Coff product value. That is, the on-resistance of the device is multiplied by the turn-off capacitor. By increasing the device size, the on-resistance of the device can be reduced, but at this point the turn-off capacitance value increases at the same rate, reducing the available bandwidth and degrading the high-frequency isolation. Switches made by Peregrine 's ultra-thin silicon (UTSi) RF CMOS technology are making rapid progress in improving Ron*Coff parameters. The UTSi switch has made tremendous progress in the past three years, and more improvements are on the agenda.
Since the thus manufactured SP4T (single-pole four-throw) switch GaAs performance equivalent to the performance of the switch and for large ones is larger than GaAs, so as the multi-mode multi-band mobile phone of this trend caused by increased complexity, the RF CMOS technology will become even more important. Since the multiplexer is basically the first device after the antenna, it can be used as a basis for integrating adjacent functions such as filters, matching networks, power amplifiers (PAs), and low noise amplifiers (LNAs) .
Peregrine 's development plan is to further integrate more functions, first of all to integrate some of the functions currently in the power amplifier module. RF, passive, and digital circuits in the power amplifier module, including bias circuits, output matching, and power control circuits, can be integrated into the monolithic chip with the antenna switch. A fully insulated sapphire substrate is capable of producing high quality factor passive components with no voltage coefficient or capacitive substrate coupling problems. The EEPROM can be integrated without additional masking steps, so that the amplifier's correction factor can be stored locally. This E ^ 2 function has been applied to integrate the E ^ PLL 2, ideal for a fixed frequency applications. The development plan includes the successful placement of the drive, and on this basis, a new type of power amplifier unit can be designed to perform pre-distortion or polarization modulation using the E^2 lookup table.
Since sapphire is transparent from the ultraviolet (UV) to infrared (IR) bands, the UTSi CMOS process is used to fabricate high performance parallel optical interconnect devices.
Figure 3 Â The optical flip chip based on the UTSi
Figure 3 shows a 10 Gbps bidirectional ( transmit and receive ) parallel optical module fabricated in a UTSi CMOS process . By connecting a vertical cavity surface emitting laser (VCSEL) and a PIN photodetection diode to the driver circuit ( laser driver circuit and TIA/LA) in a flip chip manner , almost all problems related to bonding parasitic parameters and alignment can be solved. . Laser alignment of the locating holes on the sapphire substrate provides mechanical self-alignment to ensure reliable optical coupling.
Lc Fiber Coupler,Lc To Sc Coupler,Sc To Lc Coupler,Mpo To Lc Adapter
Ningbo Fengwei Communication Technology Co., Ltd , https://www.fengweifiberoptic.com