LAN8720 datasheet(10/79 Pages) SMSC

10 / 79 page

Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support

Datasheet

Revision 1.0 (05-28-09)

SMSC LAN8720/LAN8720i

DATASHEET

1.3

Architectural Overview

The LAN8720/LAN8720i is compliant with IEEE 802.3-2005 standards (RMII Pins tolerant to 3.6V) and

supports both IEEE 802.3-2005 compliant and vendor-specific register functions. It contains a full-

duplex 10-BASE-T/100BASE-TX transceiver and supports 10-Mbps (10BASE-T) operation, and 100-

Mbps (100BASE-TX) operation. The LAN8720/LAN8720i can be configured to operate on a single 3.3V

supply utilizing an integrated 3.3V to 1.2V linear regulator. An option is available to disable the linear

regulator to optimize system designs that have a 1.2V power supply available. This allows for the use

of a high efficiency external regulator for lower system power dissipation.

1.3.1

Configuration

The LAN8720 will begin normal operation following reset, and no register access is required. The initial

configuration may be selected with configuration pins as described in Section 5.3.9. In addition,

transceiver. For example, the device can be set to 10BASE-T only. The LAN8720 supports both IEEE

802.3-2005 compliant and vendor-specific register functions.

Figure 1.1 LAN8720/LAN8720i System Block Diagram

LAN8720

Ethernet

Transceiver

MODE

RMII

LED Status

10/100

Ethernet

MAC

Crystal or

Clock Osc

MDI

Transformer

RJ45

LAN8720 데이터시트(PDF) 10 Page - SMSC Corporation