The most popular use of RF reference module to acc

2022-07-29
  • Detail

Using RF reference modules to accelerate OEM product design and implementation

although the popularization and development of wireless technology continues to lead the speed of most relevant engineering elements, it is still impossible for OEMs to achieve a complete design by purchasing ready-made RF chips and connecting them with antennas. Factors such as impedance matching and PCB layout optimization pose great challenges to RF design. Wireless IC manufacturers have invested a lot of time and money in the process of chip development and silicon chip level to solve various design challenges. However, there is still a long way to go from a well-designed RFIC to its successful integration into OEM products. Therefore, the RF reference module came into being, which provides convenience for OEM to design applications around the chip

preliminary test

before making a decision to invest a lot of money and time in the R & D of an RF chip, the first step that OEMs want to do is to evaluate the performance of the RFIC. The RF reference module provides such a platform, which is usually used in conjunction with a development or Evaluation Kit with the required firmware. The module can be used for indoor or outdoor coverage distance test. With this module, the OEM can roughly understand the actual performance of the RF chip

Figure 1: cy3630m reference module with PCB trace antenna

because the wireless IC manufacturer has invested considerable time and resources in optimizing the reference module, the product developer needs to evaluate only the mapping benchmark performance of RF. This avoids the risk that OEMs start to design based on the chip only based on the data manual specifications rather than the actual performance. Therefore, the return on investment (ROI) risk is significantly reduced

detailed test

when the antenna is replaced by SMA or micro coaxial connector (see Figure 2), another way to realize the RF reference module can be realized. This process simplifies the implementation of conducted RF measurements up to the antenna end circuit link. This module also makes it possible to further study the matching network of RF pin back link and measure the return loss and impedance by using network analyzer. This enables OEMs to modify the matching network according to the antenna they intend to use. With the help of spectrum analyzer or power meter, conduction measurement such as peak RF output power of different power amplifier levels can be carried out. Stray harmonics in the frequency band of interest can also be measured. The frequency band occupied by the transmitter and the conducted spurious of the receiver can be measured and detected to determine whether they meet the wireless control protocol

Figure 2: reference module with SMA

pcb layout and schematic design points

rf reference module provides the schematic diagram of typical application circuit using the RF chip and the optimized PCB layout meeting the specification of the module. The manufacturer has provided RF layout engineers with sufficient resources to modify and optimize the PCB in order to ensure the best performance. Therefore, RF chip manufacturers have corrected some mistakes that OEM may make in layout. These possible errors include: (a) improper placement of devices below the RF output matching circuit where sideband noise can be introduced; (b) The fragmented earth potential isolated island that can reduce the performance of the receiver by several dB, so the production cost is lower; (c) Arrange mechanical components such as screws near the antenna, which is easy to detuning the antenna; (d) Closed wiring errors that can cause ESD failure

the PCB trace line width of the reference module takes into account the requirements of different signals (such as power lines and transmission lines for transmission output). In addition, manufacturers usually lead important IC pins out to the terminal strip or test points to facilitate the test as a new generation of materials. If the OEM plans to use the external power amplifier to increase the transmission power to expand the coverage, the reference module can provide several pins of the driving power amplifier and adopt the external rx-tx RF switching. The recommended decoupling capacitance value of power supply is adopted in the design. Another significant advantage of using the reference module is that if the manufacturer uses PCB wire antenna, you have a workable antenna design, which saves the trouble of simulating and testing various other antenna topologies. With the help of the reference module, it is easy to estimate the PC required by your design for future reference of the number of B layers and PCB thickness

raw material cost estimation and FCC certification

for low-cost applications, the number of peripheral devices required by RFIC often determines the choice between two RF chips with the same RF data index. The RF reference module can be used to accurately estimate the raw materials required and the approximate cost required to build the OEM's own module. Manufacturers generally use separators that are readily available from distributors

RF reference modules of some RF IC manufacturers have been pre certified by FCC. These RF reference modules have passed several FCC tests, such as stray emission test, output power and occupied bandwidth test, etc. Pre certification circumvents a major bottleneck faced by product developers, especially when the schematic and layout are different from the original and copy the RF reference module

summary of this article

rf reference module enables OEMs to immediately evaluate the RF chip, accurately estimate and analyze the cost of raw materials required for its application, and have fully tested design schematic and layout guidance. The OEM can copy the layout and schematic diagram of the reference module as is or use it as a starting tool so that it does not have to start from scratch. In this way, it accelerates the listing speed of its products, and then improves its return on investment. For wireless IC manufacturers, the rapid implementation of their RF chips can enable them to win important design contracts in a short time, thus bringing higher profits. Therefore, RF reference modules form a win-win symbiotic link between RF chip manufacturers and OEMs. (end)

Copyright © 2011 JIN SHI