General Description
The RTL8309SB is a 128-pin, ultra low power, high-performance 8-port Fast Ethernet single-chip switch with one extra MII port for specific applications. It integrates all the functions of a high speed switch system—including SRAM for packet buffering, non-blocking switch fabric, address management, one general use MII interface, eight 10/100Base-TX transceivers, and nine Media Access Controllers—into a single 0.18µm CMOS device. It provides compatibility with all industry standard Ethernet and Fast Ethernet devices. Only a 25MHz crystal is required; the EEPROM is optional to save BOM costs.

FEATUREs
■ Integrates eight 10/100 transceivers and nine MAC units for 10Base-T and 100Base-TX.
■ Embedded SRAM for packet storage.
■ On-chip 1024-entry look-up table in direct mapping mode.
■ Embedded 16-entry CAM for hash collision mapping.
■ Provides read/write access to look-up table entries via SMI interface.
■ Provides non-blocking wire speed reception and transmission.
■ Flow control fully supported:
   ◆ Half-duplex: backpressure flow control.
   ◆ Full-duplex: IEEE 802.3x flow control.
■ Support for 4 LEDs per-port in various combinations for comprehensive applications.
■ Optional loop detection function with an LED to indicate the existence of a loop.
■ Supports MII loopback.
■ LEDs blink upon reset for LED diagnostics.
■ Flexible system configuration by strapping pins, EEPROM, or SMI interface.
■ Optional crossover detection and auto correction for plug-and-play.
■ Fully compliant with IEEE 802.3/802.3u.
■ Optional Forwarding/Filtering reserved control frames (DID= 0180C2000003~0180C200000F).
■ Optional Broadcast Input/Output Drop flow control.
■ Optional maximum packet length 1536/1552 Bytes.
■ Supports two Power Reduction methods:
   ◆ Power saving mode (automatic cable detection).
   ◆ Power down mode (via PHY register 0.11).
■ Supports QoS function:
   ◆ QoS based on: (1) Port-based priority (2) 802.1p VLAN tag (3) DiffServ/TOS field in TCP/IP header (4) IP address.
   ◆ Supports two-level priority queues with various weighting ratios.
   ◆ Queue service rate based on weighted round robin algorithm.
   ◆ Optional auto turn off Flow Control for 1~2 sec to avoid head-of-line blocking.
■ Supports MII interface connection to external MAC or PHY via 3 modes.
   ◆ PHY mode MII for router applications.
   ◆ PHY mode SNI for router applications.
   ◆ MAC mode MII for HomePNA or other PHY applications.
■ Flexible 802.1Q port/tag-based VLAN.
   ◆ Optional 802.1Q tag-VID aware function.
   ◆ Optional VLAN Ingress Tag Admit Control.
   ◆ Optional VLAN Ingress Member set filtering.
   ◆ Optional ARP VLAN for broadcast packet.
   ◆ Optional Leaky VLAN for unicast packet.
■ Optional 802.1P/Q tag insertion or removal on per-port basis (egress).
■ 25MHz crystal input.
■ 0.18µm, CMOS technology.
■ 128-pin PQFP package.
■ 1.8V core voltage.
■ Independent power options for 2.5V or 3.3V MII interface.