April 2007

Rev 1

1/10

AN2484

Application note

STOTG04 in power down mode

Introduction

A standard USB bus is based on a host-peripheral topology, where the host is typically a PC

which manages the peripherals connected to the bus.

The need to interconnect mobile devices is the purpose for the development of the "OTG

supplement to the USB 2.0 specification" the main target of which is to add host functionality

to devices originally intended as peripherals in USB 2.0.

Battery-powered equipment, such as PDAs and mobile phones, are typical applications for

USB OTG, and therefore for the STOTG04 USB OTG transceiver.

Because increasing battery life is a constant challenge in these products, the STOTG04

implements a power-down operating mode to decrease power consumption. The amount of

current drawn by the transceiver in this mode is dependent on its configuration. This

document is intended to assist in the programming of the STOTG04's internal registers to

achieve minimum power consumption.

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