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 802.3 Ethernet/Thin-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 Mbit/s data from the transceiver into NRZ
data for the controller.
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 802.3; 10BASE5,
10BASE2, and 10BASE-T
Y
Designed to interface with 10BASE-T transceivers
Y
Functional and pin-out duplicate of the DP8391
Y
10 Mbits/s Manchester encoding/decoding with receive
clock recovery
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 802.3 compatible network as
shown below. The DP83910A is a functionally complete
Manchester encoder/decoder including a balanced driver
and receiver, on-board crystal oscillator, collision signal
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
translator, and
a
diagnostic loopback feature. The
TTL/MOS compatible controller interface
1.0 System Diagram
IEEE 802.3 Compatible Ethernet/Thin-Ethernet/10 BaseT
Local Area Network Chip Set
TL/F/9365–1
TRI-STATEÉ is a registered trademark of National Semiconductor Corporation.
C
1995 National Semiconductor Corporation
TL/F/9365
RRD-B30M105/Printed in U. S. A.