Microchip Technology KSZ8342Q

Overview

KSZ8342Q from Micrel is a highly integrated VoIP system-on-chip combining a MIPS32 4KEc CPU core, ZSP voice DSP engine, and a 3-port Ethernet switch with IEEE 802.3u 10/100BASE-TX PHYs. It supports Energy Efficient Ethernet (EEE), IEEE 802.1Q VLAN, IGMP snooping, and hardware-accelerated PCM/SPI SLIC interfaces for analog telephony gateways and IP PBX systems.

For engineers reviewing the KSZ8342Q datasheet, KSZ8342Q pinout, KSZ8342Q application, or KSZ8342Q equivalent, this page delivers verified technical context on its dual-processor architecture, 128-pin PQFP package, embedded switch QoS features, SDRAM/Flash memory interface timing, and real-time voice processing capabilities - all critical for VoIP gateway BOM validation and layout design.

Technical Context

The KSZ8342Q implements a tightly coupled dual-core architecture: a MIPS32 4KEc RISC processor handles protocol stack execution (SIP, RTP, TCP/IP), while a dedicated ZSP500 DSP core performs real-time voice coding (G.711, G.729A/B), echo cancellation, and DTMF detection. Both cores share a unified memory map via an internal AXI-like bus fabric.

Its integrated 3-port switch includes two 10/100BASE-TX PHYs (Ports 1–2) and one MII/RMII interface (Port 0), supporting port-based and 802.1p priority queuing, tail-tagging mode for external switch cascading, and hardware-assisted IGMPv2/v3 snooping - enabling deterministic latency for voice traffic in multi-device VoIP deployments.

Key Specifications

Pinout & Package

KSZ8342Q uses a 128-pin Plastic Quad Flat Package (PQFP) with 0.65 mm lead pitch and 20 mm × 20 mm body size. Pin assignments are defined in Table 2 of the official datasheet (Rev. 1.0, p.14), covering dedicated signal groups for CPU, ZSP, switch PHYs, memory, and peripheral interfaces.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar VoIP SoC applications.

Compared with KSZ8342Q, KSZ8863ML trades voice DSP capability for lower cost and smaller footprint in light-duty VoIP bridges, while BCM6368KPFBG adds DSL connectivity at the expense of analog telephony integration - making KSZ8342Q uniquely suited for standalone Ethernet-based analog gateway designs.

Availability

KSZ8342Q is available at Aetrix Electronics and suitable for VoIP residential gateways, small-office IP PBX systems, and hotel multi-dwelling unit telephony platforms requiring stable component supply, long-lifecycle support, and RoHS-compliant manufacturing.

Supply support for KSZ8342Q includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Micrel Inc. was a U.S.-based semiconductor company specializing in analog, mixed-signal, and communications ICs before its acquisition by Microchip Technology in 2015. Known for high-reliability Ethernet PHYs and VoIP SoCs.

The KSZ8342Q belongs to Micrel's KSZ83xx VoIP processor family, designed specifically for carrier-grade analog telephony gateways requiring integrated voice DSP, Ethernet switching, and low-power operation in compact form factors.

FAQ

What is the primary function of the KSZ8342Q in a VoIP system?

The KSZ8342Q functions as a complete VoIP system-on-chip, integrating a MIPS32 CPU for protocol stack execution (SIP, RTP), a ZSP500 DSP for real-time voice coding (G.711/G.729A), and a 3-port 10/100 Mbps Ethernet switch with embedded PHYs. In a typical deployment, the KSZ8342Q digitizes analog voice, encapsulates it into IP packets, and forwards them over Ethernet - eliminating the need for separate processor, DSP, and switch ICs. Its unified architecture ensures deterministic latency critical for voice quality.

Does the KSZ8342Q support Energy Efficient Ethernet (EEE)?

Yes, the KSZ8342Q supports IEEE 802.3az Energy Efficient Ethernet (EEE) on both integrated 10/100BASE-TX PHYs (Ports 1 and 2). EEE enables dynamic power reduction during link idle periods by transitioning the PHY into low-power idle (LPI) mode while maintaining link synchronization. This feature reduces average power consumption by up to 50% in lightly loaded VoIP sessions - a key advantage for fanless residential gateways where thermal headroom is limited. The KSZ8342Q implements EEE compliant with clause 78 of IEEE 802.3.

What memory types does the KSZ8342Q support for boot and runtime operation?

The KSZ8342Q supports booting from SPI Flash memory (up to 16 MB) and runtime execution from external 16-bit SDRAM (up to 64 MB). Its flash interface operates at up to 33 MHz with 1-/2-/4-bit SPI modes, while the SDRAM controller complies with JEDEC-standard SDR SDRAM timing (tRCD = 20 ns, tRP = 20 ns). The KSZ8342Q uses a unified memory map where boot code resides in flash, and application code/voice buffers execute from SDRAM - enabling efficient separation of persistent storage and volatile working memory.

Can the KSZ8342Q interface directly with SLIC chips?

Yes, the KSZ8342Q includes a dedicated SPI SLIC interface compliant with industry-standard SPI protocols used by common SLIC devices such as the Silicon Labs Si3217x series. This interface supports full-duplex SPI communication at up to 25 MHz, with configurable CS polarity and clock phase - allowing direct connection to SLIC without level shifters or glue logic. The KSZ8342Q also provides GPIO-controlled reset and power-down signaling for SLIC management, simplifying analog line card design.

What is the package type and pin count of the KSZ8342Q?

The KSZ8342Q is packaged in a 128-pin Plastic Quad Flat Package (PQFP) with 0.65 mm lead pitch and 20 mm × 20 mm body dimensions. This RoHS-compliant package is specified in Figure 32 of the official datasheet (Rev. 1.0, p.92) and uses standard land patterns per Figure 33. The 128-pin count accommodates dedicated buses for SDRAM, Flash, PCM, SPI SLIC, UART, and GPIO - ensuring signal integrity for high-speed digital and sensitive analog telephony interfaces within the KSZ8342Q.