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Microsemi and Broadcom Collaborate to Deliver Reverse Power Feed

October 22, 2014 by Jeff Shepard

Microsemi Corporation today introduced its new reverse power feed (RPF) technology, a critical technology for FTTdp and G.fast deployments. G.fast, the new xDSL standard for 1gbps over copper, has a maximum expected range of 250 meters (m). In order to achieve the highest data rates with G.fast, shorter loop lengths are required which leads to the need for fiber to the distribution point, or FTTdp. These fiber-fed distribution point units (DPUs) in some cases will require reverse power feed, either due to the location of the DPU, regulations of countries or economic reasons related to power grid hookup and monitoring the grid with a smart meter. Microsemi's RPF for DSL applications are designed to be used in conjunction with the VDSL2 and G.fast chipsets from Broadcom Corporation.

Reverse Power Feeding (RPF) is a new technology being standardized by ETSI and the Broadband World Forum. It allows sending power from the customer premises to a Distribution Point (DP), in order to power the Distribution Point Unit (DPU). The DPU includes typically a DSL Access Multiplexer (DSLAM) that can support up to 24 users and an Optical Network Terminator (ONT), which connects the DPU to a Central Office (CO) where the Optical Line Terminator (OLT) is located. RPF is a critical technology for the upgrade of VDSL2 subscribers to the new G.FAST standard, which has a maximum range (at high speeds) of 250m. Given that only a small amount of subscribers is located at a radius of 250m from a DPU, the number of DPUs required to deploy G.FAST infrastructure greatly increases, compared to VDSL2 and older xDSL technologies. RPF reduces installation cost by removing the new to connect the DPU locally to the power grid, and to monitor its power consumption with a smart meter.

"We're excited to leverage our expertise in both DSL and remote powering applications to expand Microsemi's portfolio in the broadband market in collaboration with Broadcom," said Iris Shuker, director of product line management at Microsemi. "PD81001 RPF PSE used in the CPE paired with PD70101 RPF PD used in the DPU are based on mature technology which is being standardized in ETSI and BBF, and enables fast deployment of advanced DSL technologies with reverse power feed. Our solution is based on a metallic-signature handshake protocol and provides Broadcom's DSL devices with inherent reliability and cost advantages over more complex communication based solutions."

"Broadcom is enabling advanced DSL broadband solutions with data rates that can reach 1 Gigabit per second," said Jim McKeon, senior director of product marketing, Broadband Carrier Access at Broadcom. "Microsemi's new RPF solutions simplify the deployment of FTTdp, allowing operators to reduce CAPEX and in turn foster the development of even more cost-effective DSL solutions."

PD81001 is RPF PSE chip with integrated low Rdson FET and features: Only 10 external components with built in 3.3Vdc output; Supports 10-, 15-, 21- and 30-Watt RPF classes with single dc voltage input (32-57 Vdc); Provides powered device protection such as over load, under load, over voltage, over temperature and short circuiting; Inherent phone off-hook protection; and PSE line monitoring capability through SPI.

PD70101 is RPF PD chip with integrated pwm controller and features: Integrated low Rdson isolating FET switch with inrush current limit; Over load and short circuit protection; Signature resistor is disconnected upon detection; Two out-of-phase driver stages for efficient synchronous rectification or active clamp. PD81001 is fixed at 4 x 5 mm 24-pin QFN package. PD70101 is fixed at 5 x 5 mm 32-pin QFN package. The RPF ICs are commercially available.