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Zarlink Semiconductor Inc.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 2003, Zarlink Semiconductor Inc. All Rights Reserved.
Features
4 10/100 Mbps auto-negotiating RMII ports
1 10/100 Mbps auto-negotiating MII/serial port
(Port 4) that can be used as a WAN uplink or as a
5th port
External I
2
C EEPROM for power-up configuration
- Default mode allows operation without external
EEPROM
Up to 4 port-based VLANs
Full wire-speed layer 2 switching on all ports (up
to 1.448 M packets per second)
Internal 1 k MAC address table
- Auto address learning
- Auto address aging
Leading edge QoS capabilities provided based on
802.1p and IP TOS/DS field
- 2 queues per output port
- Packet scheduling based on Weighted Round-
Robin (WRR) and Weighted Random Early
Detection/Drop (WRED)
- Without flow control can drop packets during
congestion using WRED
- 2 levels of packet drop provided
Supports both Full/Half duplex ports
Supports external parallel port for configuration
updates
Port 3 can be used to mirror traffic from the other
3 ports (0-2)
Provides port-based prioritization of packets on up
to 2 ports (0-1)
- Input ports are defined to be high or low priority
- Allows explicit identification of IP Phone ports
Ports 0 & 1 can be trunked to provide a 200 Mbps
link to another switch or server
Utilizes a single low-cost external Pipelined,
SyncBurst SRAM (SBRAM) for buffer memory
- 256 k bytes or 512 k bytes (1 chip)
Flow Control capabilities
- Provides back pressure for half duplex
- 802.3x flow control for full duplex
Special power-saving mode for inactive ports
Ability to support WinSock2.0 and Windows2000
smart applications
Transmit delay control capabilities
- Provides maximum delay guarantee (<1 ms)
- Supports mixed voice-data networks
Optimized pin-out for easy board layout
November 2003
Ordering Information
MDS105AL
208 Pin PQFP
-40
C to +85C
MDS105
Unmanaged 5-Port 10/100 Mbps
Ethernet Switch
Data Sheet
Figure 1 - System Block Diagram
MDS105
5-Port
Switch
Chip
S
S
R
A
M
10/100
Phy
10/100
Phy
Quad
RMII
MII
MDS105
Data Sheet
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Zarlink Semiconductor Inc.
Description
The MDS105 is a fully integrated 5 port Ethernet switch designed to support the low-cost requirements of
unmanaged switch applications. The MDS105 provides features that are normally not associated with plug-and-
play technology, while not requiring an external processor to facilitate their utilization.
The MDS105 begins operating immediately at power-up, learning addresses automatically and forwarding packets
at full wire-speed to any of its four output ports or the uplink expansion port. The default configuration allows
operation without using an external EEPROM.
With an EEPROM to configure the device at power-up, however, the MDS105 provides flexible features: port
trunking, port mirroring, port-based VLANs, and Quality of Service (QoS) capabilities that are usually associated
only with managed switches.
The built-in intelligence of the MDS105 allows it to recognize and offer packet prioritization using Zarlink's QoS
scheme. Packets are prioritized based upon their layer 2 VLAN priority tag or the layer 3 Type-Of-
Service/Differentiated Services (TOS/DS) field. This priority can be defined as transmit and/or drop priority.
The MDS105 can be used to create a 4 port unmanaged switch with one WAN router port by connecting a CPU
(ARM or MPC 850) to the additional MII port (Port 4). The only external components needed are the physical layer
transceivers and a single SBRAM, resulting in a low total system cost.
Designed to support the requirements of converging networks, the MDS105 utilizes a power conserving
architecture. To further enhance this power management, the chip automatically detects when a switch port is not
being utilized, and turns off the logic associated with that port, thereby saving power and reducing the current load
on the switch power supply.
Operating at 66 MHz internally, and with a 66 MHz interface to the external SBRAM, the MDS105 sustains full wire-
speed switching on all 5 ports.
The chip is packaged in a small 208 pin Plastic Quad Flat-Pak (PQFP) package.
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