Features: *
Low cost Fast Ethernet Switching Controller.
-Provide packet switching functions between eight
10/100Mbps, auto-negotiated on-chip Fast
Ethernet ports and a proprietary Full-duplex
Expansion port.
-Cascade max. 8 DM8108s without extra glue
logic for 64-port configuration.
* Incorporates three 802.3 compliant 10/100Mbps
Media Access Controllers
- Direct interface to MII (Media Independent
Interface)
-Half/Full Duplex Support for individual port (up-to
200Mbps/port)
-IEEE 802.3 100Base-TX, T4.FX compatible
* Auto-negotiation supported through Serial MII interface
*High-performance Distributed Switching Engine
- Performs packet forwarding and filtering at full
wire-speed
-148,800 packets/sec. on each Ethernet port
*Direct support for packet buffering
- Glue-less interface with 1 or 2 Mbytes of SDRAM(SGRAM)
- 32 bit memory bus configuration
-66 Mhz 90Mhz memory bus speed
- Up-to 1.1K buffers, 1536-byte each, allocated to receive ports
*Support Store and Forward switching approach
-Low last-bit to first-bit out delay
-Allow mixed speed Ethernet packet switching
-Allow conversion between different protocols
*Flow control
-Support partitioning function
-Support back-pressure while lack of internal resources
- Support 802.3x PAUSE function in full duplex mode
-Support up to 4-port trunking for 800Mbps bandwidth
* Advanced Address Learning and Searching
-Self learning mechanism
-Cache 128 address entries internally
-Record up-to 16K Uni-cast MAC addresses and unlimited Multicast and Broadcast addresses
-Automatic aging scheme
-Broadcast filtering rate control
*Expansion Bus
- Up-to 8 SW devices can be cascaded via expansion bus without extra logic
-Full duplex mode transfer
-Less Bus overhead
-Automatic flow control
*Complete status report to a simple LED interface
*Suitable for low cost Switch market to replace Hub
*0.35 m process, 3.3V with 5V tolerant I/O
*208-pin PQFP package
Pinout
Specifications
| Symbol |
Parameter |
Min. |
Max. |
Unit |
Conditions |
| Vcc |
Supply voltage |
-0.3 |
3.6 |
V |
|
| Vi |
Input voltage |
-0.3 |
5.25 |
V |
|
| Vo |
Output voltage |
-0.3 |
Vcc + 0.3 |
V |
|
| Io |
Output Current |
2 |
24 |
mA |
|
| Iik |
Input protection diode current |
|
|
mA |
|
| Iok |
Output protection diode current |
|
|
MA |
|
| Tc |
Operating temperature |
0 |
70 |
C |
|
| Tstg |
Storage temperature |
-40 |
125 |
C |
|
| ESD |
Static Discharge voltage |
2000 |
|
V |
|
Description The DM8108 is an 8 port 10/100Mbit/s nonblocking Ethernet switch with on-chip address-lookup engine. The DM8108 provides a low-cost, high-performance switch solution with PHYs and single SGRAM.
The DM8108 provides eight 10/100Mbit/s Fast Ethernet interface. In half-duplex mode, all ports support back-pressure capability to reduce the risk of data loss for a long burst of activity. In the full-duplex mode of operation, the device uses IEEE std. 802.3 frame-based pause protocol for flow control. With full-duplex capability, port 0 7 support 1.6Gbit/s aggregate bandwidth connections. The DM8108
also supports port trunking/load balancing on the
10/100Mbit ports. This can be used to group ports on i switch links to increase the effective bandwidth between the systems.
The internal address-lookup engine supports up to 16.25K unicast and unlimited multicast and broadcast addresses.This engine performs destination and source addresses book-keeping and comparison which also forwards unknown destination address packets to all ports.
The DM8108 is fabricated with a .35um technology.Working at 3.3V, the inputs are 5V tolerant and the outputs are capable of directly driving at TTL levels.
DM8108 Data Sheet
