NXP offers tools to design solid-state RF energy products

By Brian Santo, contributing writer

Yet another mainstay of classic analog engineering, the magnetron, is being targeted for silicon replacement. In the last year or so, RF semiconductors aimed at heating applications have started to reach the market. These RF ICs promise to consume significantly less power and deliver superior precision controlling temperatures. NXP is among those offering these RF ICs and has launched a set of tools that engineers can use to design and prototype systems based on RF energy semiconductors.

NXP is offering turnkey solutions and reference designs for industrial, scientific, and medical applications to help designers transition from legacy vacuum tube-based systems to solid-state systems for efficient and controllable RF energy.

One example is microwave ovens. Traditional microwave ovens might cycle their magnetrons on and off every few seconds through the duration of the cook time. However, microwave ovens based on RF semiconductors can be cycled on and off in milliseconds (and perhaps even microseconds, if necessary) and be combined with sensors that will be able to measure the temperature of the food being heated — data that can be used to achieve finer cooking control.

There are other applications for RF energy. One is medical ablation, a process of heating human tissue, sometimes at RF and sometimes at microwave frequencies. The technique has a wide range of applications, including correcting heart arrhythmia, reducing osteoarthritic knee pain, and treating some forms of cancer. There is also a range of industrial uses that includes treating materials such as wood, ceramics and paints; warming medical materials; and chemical processing.

NXP Semiconductors announced a set of 2.45-GHz, 250-W platform solutions to help engineers prototype and develop RF energy systems. All three solutions are built around NXP’s MRF24300N 300-W LDMOS transistor, designed for 2,400-MHz to 2,500-MHz operation at 60% drain efficiency. The company claims that extensive RF expertise is not necessary to prototype with the development platforms.

The RFE Series of system solutions includes the following:

• RFEL Lab Box, a plug-and-play RF generator
• RFEM module that combines RF power transistors with a microcontroller
• RFEP Pallet, a three-stage power amplifier reference design

NXP describes the RFEL Lab Box as a plug-and-play RF generator with reflected power measurement, designed for evaluation and initial prototyping. The fully integrated lab box must be hooked up to a PC; it is controlled through a PC-based graphical user interface (GUI).

The RFEM Module includes RF power transistors and an NXP Kinetis microcontroller, supporting an application programming interface (API) that allows multiple operations such as frequency sweeps and closed-loop modes, said the company.

The company promises that, by using the box, engineers can prototype quickly and easily. Once they have a prototype in hand, engineers can then use the module and pallet to create production systems. NXP also has an existing product line of high-performance RF components with associated evaluation boards, an option for engineers who have more RF expertise.

The company said that it is building an ecosystem of skilled and vetted design houses and ODM partners willing to crank out finished designs in volume.

Full availability of the RFE Series is scheduled for September 2018. The RFEL24-500, a 2 x 250-W lab box, is priced at $10,000. It is available only for purchase by approved customers; however, according to the company’s website, each order will be reviewed prior to being fulfilled. The RFEM24-250 is a 250-W module priced at $2,500. (Two RFEM24-250 modules are included in the RFEL24-500 lab box.) The RFEP24-300 300-W pallet is priced at $1,500.

All three solutions are built around NXP’s MRF24300N RF transistor, which is shipping in volume and is part of NXP’s Product Longevity Program, which guarantees availability until at least 2026.