RF design in the 21st century: Page 6 of 7

August 04, 2016 //By Paul Dillien
My first job on leaving college was maintaining military radios. I had covered RF theory, but found that the practice was significantly different. The company’s detailed design work was performed at a remote location, and shrouded in mystery. RF design was a “black art” that only a few specialists could understand. I later moved into pure logic design, where the relative simplicity of 1s and 0s held fewer uncertainties. This ultimately led me into two decades of involvement with FPGAs.

The latest devices employ CMOS technology, which has led to enhanced cost-savings and ease-of-use features, to minimize the overall cost of ownership.

The devices require a minimum of external components, resulting in a compact physical solution. They are low power chips, consuming as little as 550 mW, and can operate using a single 1.8V supply rail, reducing the cost of the regulators and the number of board layers needed. These factors all contribute to increased system reliability because there are fewer solder joints and points of failure.

FPRFs can save time and money also during the testing and calibration process. Typically, the production line will involve stages where the RF performance is checked and aligned for optimum performance. The FPRFs offer a fast and efficient solution to this problem with RF loop-back features to test out the basic functionality. Calibration routines can be controlled from either the baseband chip or an on-chip microcontroller, providing a simple and automated capability to tune and align the various blocks to minimize off-sets.

RF designers can benefit from the highly integrated field programmable chips that are now available to bring exciting new products to market quicker than ever before.

 

Baseband companion chip

In any system there will be a requirement for baseband processing. Several options are available such as dedicated ASSPs, processors, ASIC solutions or FPGAs. All these solutions have merits and disadvantages. ASSP devices are aimed at high volume applications such as small cells (e.g. femtocells). Where the ASSP provides exactly the required functionality, it will typically be priced aggressively.

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