
PMC-Sierra,Inc.
8-Port 10 Mbit/s Switch
Preliminary
PM3350
ELAN 8x10
FEATURES
• Single-chip, 8-port, 10BaseT Ethernet 
switch device f or low-cost unmanaged 
and managed networks. 
• On-chip SmartPath 50 MHz RISC 
CPU core, multi-channel DMA 
controller, MAC-layer interface logic, 
FIFOs, PCI-based expans ion port, and 
a flexible memory controller.
• CPU supports backgro und applications 
running on local OS (e.g., SNMP), and 
real-time data-oriented applications 
(e.g., packet forwarding and filtering 
decisions).
• Concurrently switches packets 
between eight independent, halfduplex ports at the full Ethernet rate of 
10 Mbit/s.
• Fully compatible with th e PM3351, 
1-port 10/100 Mbit/s switch device; 
may be used to create a compact and 
inexpensive mixed 10/100 Mbit/s 
switching hub.
• Store-and-forward operation with full 
error checki ng and filtering.
• Low-latency operation in both unicast 
and broadcast modes.
• Filtering and switching at wire rates (up 
to 148,8000 packets per second), 
supporting a mix of Ethernet and 
IEEE 802.3 protocols.
• Performs all address learning, ad dress 
table management, and aging 
functions for up to 32,768 MAC 
addresses (limited by external 
memory) with an a ddre ss l ear nin g rate 
of up to 10,000 addresses per second.
• Maximum broadcast/multicast rate of 
14,880 packets per second per port 
with configurable broa dc ast storm rate 
limiting.
• Backpressure flow control with 
configurable per-port buff er thresho lds  
and limits.
• Expandable to 64 ports without loss in 
throughput using multiple PM3350 
devices via an on-chip 1 Gbit/s 
expansion port.
• Expansion port supports a peak  
system bandwidth of 1 Gbit/s, and is 
compatible with industry-standard PCI 
bus (version 2.1).
• Interfaces directly to industry-standard 
10BaseT Ethernet Medium Access 
Unit devices (LXT944 or similar) with 
no glue logic.
• Configuration, management, MIB 
statistics, and diagnostics available 
in-band (via on-chip SNMP agent with 
integral TCP/UDP/IP stack).
• Maintains and collects per-port and 
per-host statistics at wire rates.
• Fully static CMOS operati on at 50 MHz 
clock rates.
• Implemented with a 3.3 V core and a 
5 V-compatib le I/O.
• Available in a 256-pin Ball Grid Array 
(BGA) package.
BLOCK DIAGRAM
PCI Expansion 
Bus
PCI Bus 
Interface
Expansion 
Registers
50 MHz 
Embedded 
RISC CPU
I 
CacheD Cache
Multi-Channel 
DMA 
Controller
External 
Memory 
Interface
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
 FIFO 10BaseT MAC
10BaseT
10BaseT
Quad Ethernet 
Quad Ethernet 
10BaseT
Interface Adapter
10BaseT
10BaseT
10BaseT
10BaseT
Interface Adapter
10BaseT
PMC-970277 (P4) 
EDO DRAM/EPROM
1998 PMC-Sierra, Inc. October, 1998
 

Preliminary
 PM3350 ELAN 8x10
8-Port 10 Mbit/s Switch
TYPICAL APPLICATIONS
LOW-COST 10 Mbit/s SWITCHES
The ELAN 8×10 chip can act as a stand-alone managed or unmanaged switching device in low-cost, compact switch applications. 
Eight to sixty-four ports of 10BaseT switches can be built using the internal PCI expansion port. A typical system would use the 
following:
• PM3350 (one for every eight ports), 
• two 256k × 16-bit 60 ns EDO or Fast Page Mode DRAM chips per ELAN 8×10 chip, 
• an EPROM or EEPROM (initialization, configuration, SNMP support firmware), 
• quad Ethernet interface adapters (LXT944), and 
• appropriate passive components. 
A block diagram of a typical 8-port 10BaseT stackable sw itch is shown.
PCI Bus Expansion Bus
10BaseT 
Ports 1-4
10BaseT 
Ports 5-8
PM3350
(/$1[
EDO DRAM EEPROM
Quad 10BaseT 
Interface
Quad 10BaseT 
Interface
LOW-COST 10/100 Mbit/s SWITCHES
The ELAN 8×10 chip can be part of a fully managed 10/100 switch using the PM3351 ELAN 1×100 10/100 Mbit/s switch chip. 
Together they can form a workgroup or desktop application. A block diagram of a typical 32-port 10BaseT stackable switch with 
two 10/100 Mbit/s ports is shown. The PCI expansion bus is used to seamlessly connect the ELAN 8×10s and ELAN 1×100s.
(/$1[
DRAM
10/100BaseT
10/100 PHY
PM3351
SRAM
8×10BaseT
Quad 
Quad 
PHY
PHY
PM3350
(/$1[
8×10BaseT
Quad 
PHY
PM3350
(/$1[
EDO 
DRAM
PCI Backplane
Quad 
PHY
EDO 
Head Office: 
PMC-Sierra, Inc. 
#105 - 8555 Baxter Place 
Burnaby, B.C. V5A 4V7 
Canada 
Tel: 604.415.6000 
Fax: 604.415.6200
EEPROM
PM3350
(/$1[
Quad 
Quad 
PHY
PHY
8×10BaseT
To order documentation, 
send email to: 
document@pmc-sierra.com 
or contact the head office, 
Attn: Document Coordinator
EDO 
DRAM
PM3350
(/$1[
Quad 
Quad 
PHY
PHY
8×10BaseT
EDO 
DRAM
All product documentation is available 
on our web site at: 
http://www.pmc-sierra.com 
For corporate info rmation, 
send email to: 
info@pmc-sierra.com
(/$1[
10/100 PHY
10/100BaseT
PM3351
SRAM
PMC-970277 (P4) 
 1998 PMC-Sierra, Inc. 
October, 1998 
SmartPath is a trademark 
of PMC-Sierra, Inc.