Circuit Note

CN-0506

Rev. 0 | Page 3 of 7

CIRCUIT DESCRIPTION

Ethernet

Ethernet is the most common type of packet-based physical

connection for data networking applications in a local area network

(LAN) that is defined as subsections and specifications by the

Institute of Electrical and Electronic Engineers (IEEE) 802.3

standards.

There are different speeds and transmission medium associated

with Ethernet. However, the focus of this circuit note centers on

10BASE-T, 100BASE-TX, and 1000BASE-T over twisted pair

cables, Category 5e (CAT5e) or Category 6 (CAT6), straight

through or crossover.

Line and Ring Network Topologies

Typical industrial Ethernet networks are deployed in line or ring

topologies. The line and ring network topologies have reduced

wiring lengths compared to start networks, and a redundant

path for the ring network (see Figure 2). Each device connected

to a line or ring network requires two Ethernet ports to pass

Ethernet frames along the network.

LINE TOPOLOGY

PHY

MASTER

CONTROLLER

HOST/MAC

PHY

PHY

HOST/MAC

PHY

PHY

HOST/MAC

PHY

PHY

UP TO 100m

RING TOPOLOGY

MASTER

CONTROLLER

HOST/MAC

PHY

PHY

PHY

PHY

HOST/MAC

PHY

PHY

HOST/MAC

PHY

PHY

UP TO 100m

Figure 2. Line and Ring Topology

PHY

A PHY is the physical interface transceiver that implements the

physical layer functions of the open systems interconnection

(OSI) model. A PHY encodes and decodes the data transmitted

and received between devices, maintaining the integrity of the

frames and packets (see Figure 3).

PHY Hardware Configuration—Strapping Resistors

The ADIN1300 can be configured to power up ready to establish

a link. This PHY hardware configuration uses external strapping

resistors and provides a known configuration for power on in

an unmanaged application. Typically, in unmanaged applications,

users do not configure the PHY over the management data

input and output (MDIO). Instead, unmanaged applications rely

on the PHY hardware configuration to bring the ADIN1300 up

with the appropriate configuration ready to link with a remote

PHY partner. When the ADIN1300 powers up, the hardware

strapping pins are sampled when the device comes out of reset,

and the PHY device then knows how to configure the various

functions.

The hardware configuration modes of interest for this circuit

note are speed, PHY address, automatic medium dependent

interface crossover (Auto-MDIX), and MAC interface. The

EVAL-CN0506-FMCZ includes resistor footprints for the

various combinations, with a particular default configuration.

The resistor components can be inserted or removed if required

to change the default hardware configuration.

Consult the ADIN1300 data sheet for more information on

using the other features and functions such as energy efficient

Ethernet (EEE), energy detect power down, down speed, and

software power down.

CAT5e/CAT6

CABLE

PHYSICAL

MEDIUM

RJ45 WITH

INTEGRATED

MAGNETICS

SENSOR, ACTUATOR,

MOTOR, HMI, ETC.

MANAGEMENT

INTERFACE

MDIO

MAC

INTERFACE

RGMII/RMII/MII

HOST/

SWITCH

ADIN1300

PHY

MDI

Figure 3. Typical Networked Sensor with PHY Device