General Description
The RTL8305SC is a 5-port Fast Ethernet switch controller that integrates memory, five MACs, and five physical layer transceivers for 10Base-T and 100Base-TX operation into a single chip. All ports support 100Base-FX, which shares pins (TX+-/RX+-) with UTP ports and needs no SD+/- pins, a development using Realtek proprietary technology. To compensate for the lack of auto-negotiation in 100Base-FX applications, the RTL8305SC can be forced into 100Base-FX half or full duplex mode, and can enable or disable flow control in fiber mode.

FEATUREs
■ 5-port integrated switch controller with memory and transceiver for 10Base-T and 100Base-TX with:
   ♦ 5-port 10/100M UTP or
   ♦ 4-port 10/100M UTP + 1-port MII/SNI or
   ♦ 4-port 10/100M UTP + 1-port MAC MII/SNI + 1-port PHY MII
■ Supports the fifth port MAC circuit as PHY mode MII, SNI for router applications, and MAC mode MII for HomePNA or VDSL solutions
■ Supports the fifth port PHY circuit as PHY mode MII for router and Gateway applications
■ All ports support 100Base-FX with optional flow control enable/disable and full/half-duplex setting
■ Supports FEFI function for fiber application
■ Non-blocking wire-speed reception and transmission and non-head-of-line blocking forwarding
■ Fully compliant with IEEE 802.3/802.3u auto-negotiation function
■ Built-in high-efficiency SRAM for packet buffer, with 1K-entry lookup table and 16-entry CAM
■ Supports broadcast storm filtering function
■ Flow control fully supported:
   ♦ Half duplex: back pressure flow control
   ♦ Full duplex: IEEE 802.3x flow control
■ Supports SMI (Serial Management Interface: MDC/MDIO) for programming and diagnostics
■ Supports loop detection function with one LED to indicate the existence of a loop
■ Supports MAC and PHY loopback function for diagnosis
■ Supports up to 16 VLAN groups
■ Flexible 802.1Q port/tag-based VLAN
■ ARP VLAN for broadcast packets
■ Leaky VLAN for unicast packets
■ VLAN tag Insert/Remove function
■ Supports QoS function on each port:
   ♦ QoS based on: (1) Port-based, (2) VLAN tag, (3) TCP/IP header’s TOS/DS
   ♦ Supports two-level priority queues
   ♦ Weighted round robin service
  
■ Robust baseline wander correction for improved 100Base-TX performance
■ Optional MDI/MDIX auto crossover for plug-and-play
■ Physical layer port Polarity Detection and Correction function
■ Optional EEPROM interface for configuration
■ 25MHz crystal or 3.3V OSC input
■ Single 3.3V power input can be transformed to 1.8V via a low-cost external BJT transistor
■ Low power, 1.8/3.3V, 0.18µm CMOS technology, 128-pin PQFP package
■ Supports special VLAN tag insert or remove function on per-port basis (egress) to separate WAN traffic from LAN traffic
■ Optional 1536 or 1552 byte maximum packet length
■ Supports reserved control frames (DID=0180C2000003~0180C200000F) filtering function
■ Flexible LED indicators for link, activity, speed, full/half duplex, and collision
■ LEDs blink upon reset for LED diagnostics
■ Supports two power reduction methods:
   ♦ Power saving mode by cable detection
   ♦ Power down mode (via PHY register 0.11)
■ Robust baseline wander correction for improved 100Base-TX performance
■ Optional MDI/MDIX auto crossover for plug-and-play
■ Physical layer port Polarity Detection and Correction function
■ Optional EEPROM interface for configuration
■ 25MHz crystal or 3.3V OSC input
■ Single 3.3V power input can be transformed to 1.8V via a low-cost external BJT transistor
■ Low power, 1.8/3.3V, 0.18µm CMOS technology, 128-pin PQFP package