Broadcom BCM3349KPB: A Comprehensive Technical Overview

The Broadcom BCM3349KPB represents a highly integrated system-on-a-chip (SoC) solution designed for a specific and demanding segment of the consumer electronics market: cable modems. This chipset was engineered to provide a cost-effective yet powerful foundation for high-speed data and voice over cable systems, enabling the widespread adoption of broadband internet access.

At its core, the BCM3349KPB is built around a powerful MIPS32 CPU core. This central processing unit handles the system's control functions, protocol processing, and management of the various integrated subsystems, ensuring efficient data flow and system responsiveness. The integration of this CPU was a key factor in reducing the bill of materials for modem manufacturers, contributing to more affordable end-user products.

A primary function of the chip is signal processing. It incorporates a sophisticated digital QAM (Quadrature Amplitude Modulation) demodulator and a QPSK/QAM burst modulator. These components are essential for the cable modem's operation. The downstream receiver demodulates the high-speed data signals received from the cable network, while the upstream transmitter modulates data sent from the user back to the cable operator's headend. This robust PHY (physical layer) layer implementation ensures reliable connectivity and high data throughput.

Beyond the physical layer, the BCM3349KPB integrates a complete Media Access Control (MAC) and framing logic. This subsystem is responsible for adhering to the DOCSIS (Data Over Cable Service Interface Specification) standard, which governs communication between cable modems and the provider's equipment. Compliance with the DOCSIS standard is non-negotiable for interoperability, and this chip's integrated MAC ensures seamless operation within any compliant cable network.

Further enhancing its level of integration, the SoC includes a dedicated voice codec (coder-decoder). This feature was critical for supporting Voice over IP (VoIP) telephony services over cable, allowing service providers to offer "triple-play" services (data, video, voice) through a single device. The integration of the codec on-die simplified design for embedded multimedia terminal adapters (EMTAs).

The chip also features a comprehensive suite of interfaces to connect to external components. This includes a USB 1.1 interface for direct connection to a computer, an Ethernet MAC for connecting to a router or standalone device, and a PCI interface for internal card designs. This flexibility allowed OEMs to design a variety of product form factors, from PCI cards to external standalone modems, using the same core silicon.

In summary, the Broadcom BCM3349KPB is a hallmark of highly integrated communication processor design. It consolidated nearly all critical functions required for a DOCSIS-compliant cable modem—including CPU, PHY, MAC, and voice processing—onto a single piece of silicon. This integration drove down costs, improved reliability, and played a significant role in the mass deployment of cable broadband technology.

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DFIND

A highly integrated SoC that consolidated CPU, modem, and VoIP functions to drive the adoption of affordable cable broadband modems.

Keywords: Broadcom BCM3349KPB, DOCSIS, MIPS32 CPU, QAM Demodulator, System-on-a-Chip (SoC)