CMOS RF switch boasts cable-compatible linearity

peregrinePeregrine Semiconductor Corp. has announced the UltraCMOS PE42723, an RF switch that boasts the highest linearity specifications on the market today. An upgraded version of the successful PE42722, this new RF switch offers enhanced performance in a smaller package. Like its predecessor, the PE42723 exceeds the linearity requirements of the DOCSIS 3.1 cable industry standard and enables a dual upstream/downstream band architecture in cable customer premises equipment (CPE) devices.

The cable industry faces the challenge of supporting the consumer’s increasing demand for more high-speed home data. The rapid adoption of video-streaming services is compounding the problem and putting enormous strain on the broadband ecosystem, from CPE devices to cable infrastructure. As predicted in the Cisco Visual Networking Index (VNI), 5 million years of video content will cross the internet each month in 2019. This estimate means nearly a million minutes of video will be streamed or downloaded every second. To keep up with consumer demand, the cable industry announced the DOCSIS 3.1 standard in Oct. 2013 offering multi-gigabit throughput. The standard set an ambitious goal for the industry, and one of the toughest challenges was to support the new linearity requirements and harmonics.

The PE42722 and PE42723 switches offer a unique approach to solving the DOCSIS 3.1 linearity challenge when supporting a dual upstream/downstream band architecture. CPE devices, such as set-top boxes, cable modems and home gateways, had previously supported only one upstream/downstream band combination. The PE42722 and PE42723 are the only RF switches that enable dual upstream/downstream bands to reside in the same CPE device. By using this dual-band architecture, CPEs can comply with the DOCSIS 3.1 cable industry standard, and multi-service operators (MSOs) have the flexibility to offer their customers new and expanded services. MSOs also benefit from the switches supporting both DOCSIS 3.0 and 3.1 requirements, allowing for a simple and cost-effective transition to DOCSIS 3.1.

Before the introduction of the PE42722 in 2013, no switch had met the linearity requirements necessary to support a dual upstream/downstream band architecture. To create this architecture, the switch is placed directly at the cable modem (CM) F-connector before the filters and must comply with the stringent DOCSIS 3.1 CM spurious emissions requirements of -50 dBmV. Such a low spurious level requires the switch harmonic performance to be greater than -115 dBc. The PE42722 and PE42723 are the only RF switches available today that can achieve these high harmonic requirements.

Peregrine Semiconductor

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