Introduction

This purpose of this application note in conjunction with the VSC8201 Datasheet is to provide information to assist in the design and layout of the VSC8201 Gigabit Ethernet Transceiver.

Power Supply Organization and Decoupling

The VSC8201 requires a 3.3v and a 1.5v power supply source for operation using GMII, MII or TBI MAC interfaces. In RGMII and RTBI modes, an additional 2.5v supply is needed as specified by the RGMI/RTBI standard. The VSC8201 can be powered using the following options:

• 2 separate supplies, 3.3v and 1.5v respectively.

• A single 3.3v supply. This is done by using the optional on-chip regulator control circuit, which drives a simple external series pass type supply regulator (MOSFET) to generate the 1.5v core power supply.