P2041A-08SR Просмотр технического описания (PDF) - Alliance Semiconductor

Номер в каталоге

Компоненты Описание

производитель

P2041A-08SR

Versatile EMI Reduction IC

Alliance Semiconductor 

November 2003

P2041A

rev F

Spread spectrum selection

Table 1 illustrates the possible spread spectrum options. The optimal setting should minimize system EMI to the

fullest without affecting system performance. The spreading is described as a percentage deviation of the center

frequency (Note: the center frequency is the frequency of the external reference input on CLKIN, Pin 1).

Example of a typical printer or scanner application that operates on a clock frequency of 40 MHz:

A spreading selection of SR1=1 and SR0=1 provides a percentage deviation of +/-1.00%* (see Table 1) of Fcen.

This results in the frequency on ModOUT being swept from 40.40 MHz to 39.60 MHz at a modulation rate of

40/40*34.72=34.72 KHz (see Table 1). This particular example (see Figure below) given here is a common EMI

reduction method for scanners and has already been implemented by most of the leading manufacturers.

NOTE: Spreading range selection varies from different system manufacturers and their designs. The spreading range of P2041 can be set

to +/-2.5% when working with certain scanner model.

P2041 Application Schematic for Flat-Bed Scanner

Versatile EMI Reduction IC

Notice: The information in this document is subject to change without notice.

3 of 9

Share Link: