TLF9365

May 1995

DP83910A CMOS SNI

Serial Network Interface

General Description

The DP83910A CMOS Serial Network Interface (SNI) is a

direct-pin equivalent of the bipolar DP8391 SNI and pro-

vides the Manchester data encoding and decoding func-

tions for IEEE 8023 EthernetThin-Ethernet type local area

networks The SNI interfaces the DP8390 Network Interface

Controller (NIC) to the DP8392 CTI or an Ethernet transceiv-

er cable When transmitting the SNI converts non-return-to-

zero (NRZ) data from the controller into Manchester data

and sends the converted data differentially to the transceiv-

er Conversely when receiving a Phase Lock Loop de-

codes the 10 Mbits data from the transceiver into NRZ

data for the controller

The DP83910A operates in conjunction with the DP8392

Coaxial Transceiver Interface (CTI) and the DP8390 Net-

work Interface Controller (NIC) to form a three-chip set that

implements a complete IEEE 8023 compatible network as

shown below The DP83910A is a functionally complete

Manchester encoderdecoder including a balanced driver

and receiver on-board crystal oscillator collision signal

translator

and

a

diagnostic

loopback

feature

The

DP83910A fabricated CMOS typically consumes less than

70 mA of current However as a result of being CMOS the

DP83910A’s differential signals must be isolated in both

Ethernet and thin wire Ethernet

Features

Y

Compatible with Ethernet I

IEEE 8023

10BASE5

10BASE2 and 10BASE-T

Y

Designed to interface with 10BASE-T transceivers

Y

Functional and pin-out duplicate of the DP8391

Y

10 Mbitss Manchester encodingdecoding with receive

clock recovery

Y

Requires no precision components

Y

Loopback capability for diagnostics

Y

Externally selectable half or full step modes of opera-

tion at transmit output

Y

Squelch circuitry at the receive and collision inputs to

reject noise

Y

TTLMOS compatible controller interface

10 System Diagram

IEEE 8023 Compatible EthernetThin-Ethernet10 BaseT

Local Area Network Chip Set

TLF9365 – 1

TRI-STATE

is a registered trademark of National Semiconductor Corporation

C1995 National Semiconductor Corporation

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