October 1997
DP83959
8-Port Lite Ethernet Repeater Interface Controller
General Description
Features
The DP83959 8-Port Lite Ethernet Repeater Interface
Controller (LERIC8) is a single chip solution for unman-
aged 10BASE-T Ethernet repeater (hub) products. By inte-
grating electronics needed to support eight 10BASE-T
ports, a full level/drive compatible AUI port for a backbone
connection, and an internal power on reset circuit, a
LERIC8 based design requires only the addition of a few
passive components: crystal, transformers, connectors
and a power source.
■ Fully IEEE 802.3 Ethernet Repeater compliant
■ Eight IEEE 802.3 10BASE-T compliant ports with
on-chip transmit filters
■ One IEEE 802.3 compatible AUI port
■ Direct drive status LED outputs
■ Network traffic level monitor with direct drive LED
outputs
■ Automatic internal power-on reset function. External
TTL compatible reset pin provided for device testing if
required
■ Inter-LERIC™ bus for cascading up to 3 devices on a
single board
■ Register/LED status interface compatible with
DP83955/6 LERIC™ products
■ Single 20 MHz crystal or external 20 MHz oscillator
module operation
■ Single 5V supply
■ 160 pin PQFP package
The LERIC8 provides on-chip LED drivers that connect di-
rectly to LEDs via series resistors. In addition to the Link
OK, Port Partition, Global Activity and Global Collision LED
outputs, the LERIC8 provides an on chip network traffic
level monitor circuit with 8 LED outputs to drive a bargraph
type display.
The LERIC8 also provides an LED and Inter Repeater Bus
interface that is compatible with the DP83955/6 LERIC™
products.
1.0 System Diagram
Status LEDs (Optional)
20MHz
Inter Repeater Bus
Oscillator
Network Traffic Bargraph
Alert (High Traffic or Long Partition)
Per 10BASE-T Port Link & Partition
(Optional)
AUI Port Partition
or Crystal
Global Activity, Global Collision
DP83959 LERIC8
8-Port Lite Ethernet Repeater Interface Controller
Transformer
Transformer
Transformer
Transformer
Transformer
Transformer
Transformer
Transformer
Transformer
AUI
Port
10BASE-T
Port 1
10BASE-T
Port 2
10BASE-T
Port 3
10BASE-T
Port 4
10BASE-T
Port 5
10BASE-T
Port 6
10BASE-T
Port 7
10BASE-T
Port 8
TRI-STATE® is a registered trademark of National Semiconductor Corporation.
LERIC™ and Inter-LERIC™ are trademarks of National Semiconductor Corporation.
©1997 National Semiconductor Corporation
www.national.com