November 2006

P2041A

rev 0.2

Versatile EMI Reduction IC

3 of 8

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

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 XIN/CLK, Pin 1).

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

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

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

(40/40)*34.72 = 34.72KHz (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 P2041A can be set to +/-2.5% when

working with certain scanner model.

P2041A Application Schematic for Flat-Bed Scanner

Absolute Maximum Ratings

Symbol

Parameter

Rating

Unit

Voltage on any pin with respect to Ground

-0.5 to +7.0

V

Storage temperature

-65 to +125

°C

Operating temperature

-40 to +85

°C

Max. Soldering Temperature (10 sec)

260

°C

Junction Temperature

150

°C

Static Discharge Voltage

(As per JEDEC STD22- A114-B)

2

KV

Note: These are stress ratings only and are not implied for functional use. Exposure to absolute maximum ratings for prolonged periods of time may affect

device reliability.

1

2

3

4

8

7

6

5

VDD

SR0

ModOUT

SSON

VSS

SR1

XOUT

XIN/CLK

P2041A

VDD

Modulated 40MHz signal with ± 1.00%

Deviation

and

modulation

rate

of

34.72KHz. This signal is connected back

to the clock crystal Input pin of the

system ASIC.

NOTE: The above schematic indicates

The exact setting of this example:

Default setting (no connection on pin 3,

7 and 5)

40MHz

0.1µF