Broadcom Announces BCM4708x and BCM5301x SoCs for 802.11ac routersby Brian Klug on June 5, 2012 8:01 AM EST
We've been talking about 802.11ac a lot lately, and today Broadcom is announcing a new family of SoCs with greater integration and performance specifically tailored to 802.11ac SMB and home networks. If you haven't heard of or read our existing 802.11ac coverage, the super quick primer is that 802.11ac is a 5 GHz specific successor to 802.11n that brings higher throughput by increasing channel bandwidth to 80 MHz (with an option for 160 MHz), bringing higher order modulation (256QAM), increasing the number of available spatial streams (up to 8), and adding multi-user MIMO plus beamforming.
The news out of Broadcom today is the announcement of two new SoCs which are closely related - the StrataGX BCM5301x for SMB applications, and BCM4708x for home and home office use cases. These two SoCs are built on the same TSMC 40nm RF CMOS process that Broadcom's 802.11ac and new combo chips are built on (like BCM4334). What's new and unique about these is that they represent the first time a networking SoC of this class has integrated everything an OEM needs to make a router but the transciever - in this case a GigE ethernet switch, 5 port GigE PHY, USB 3.0 controller, standard I/O, and two PCIe 1x Gen 2.0 lanes (or three if the OEM opts to not use that I/O for USB 3.0).
The SoC is built around two ARM Cortex A9s with 256 KB of L2 cache. There's no NEON MPE since this isn't needed for a router platform, and Broadcom tells me that BCM4708x can clock those A9s up to 800 MHz, and 1 GHz for BCM5301x. Both A9 cores and ports on the switch are fully power gated, which enables the SoC to draw under 100mW at idle and switch into a the highest performance state within milliseconds. The SoC also supports up to single channel PC DDR3 1600 as opposed to the more commonly supported PC DDR2 800 for current router SoCs.
The obvious high-end platform configuration for a Broadcom-based 802.11ac router thus becomes a BCM4708x with two BCM4360s (one transceiver for 2.4 GHz 802.11n, another for 5 GHz 802.11ac) connected over PCIe 1x. Integrators will also likely differentiate with lower-end configurations without simultaneous dual band, or perhaps include BCM4331 alongside BCM4360.
When you compare to the previous generation of simultaneous dual band 3x3:3 routers, or some of the initial 802.11ac routers which shipped with BCM4706 as the SoC, which consists of a 600 MHz MIPS32, PC-DDR2, USB 2.0 and PCIe 1x Gen 1, it's easy to see the new SoC offering a considerable performance boost. Broadcom told me moving to this new platform offers a 5x boost in performance over its predecessor. Both the BCM5301x and BCM4708x are sampling, with volume production slated for the second half of 2012.