© Semiconductor Components Industries, LLC, 2011

August, 2011 − Rev. 3

1

Publication Order Number:

ASM3P2811A/D

ASM3P2811A/B,

ASM3P2812A/B,

ASM3P2814A/B

Low Power EMI Reduction IC

Description

The ASM3P28XX devices are versatile spread spectrum frequency

modulators designed specifically for a wide range of input clock

frequencies from 10 MHz to 40 MHz. Refer to Input/Output

Frequency Range Selection Table. The ASM3P28XX can generate an

EMI reduced clock from crystal, ceramic resonator, or system clock.

The ASM3P28XX−A and the ASM3P28XX−B offer various

combinations of spread options and percentage deviations. Refer to

Frequency Deviation and Spread Selection Table. These combinations

include Down and Center Spread, and percentage deviation range

from

±0.625% to −3.5%.

The ASM3P28XX reduces electromagnetic interference (EMI) at

the clock source, allowing system wide reduction of EMI of down

stream clock and data dependent signals. The ASM3P28XX allows

significant system cost savings by reducing the number of circuit

board layers, ferrite beads, shielding, and other passive components

that are traditionally required to pass EMI regulations.

The ASM3P28XX modulates the output of a single PLL in order to

“spread” the bandwidth of a synthesized clock, and more importantly,

decreases the peak amplitudes of its harmonics. This results in

significantly lower system EMI compared to the typical narrow band

signal produced by oscillators and most frequency generators.

Lowering EMI by increasing a signal’s bandwidth is called ‘spread

spectrum clock generation.’

The ASM3P28XX uses the most efficient and optimized

modulation profile approved by the FCC and is implemented in a

proprietary all−digital method.

Applications

The ASM3P28XX is targeted towards EMI management for memory and LVDS interfaces in mobile graphic chipsets and

high−speed digital applications such as PC peripheral devices, consumer electronics, and embedded controller systems.

Features

Clock of the Input Frequency

40 MHz

and Board Space

♦

±0.625% to −3.5%

and CY25814

and are RoHS Compliant

http://onsemi.com

SOIC−8

S SUFFIX

CASE 751BD

PIN CONFIGURATION

(Top View)

See detailed ordering and shipping information in the package

dimensions section on page 7 of this data sheet.

ORDERING INFORMATION

XOUT

VDD

FRS

ModOUT

VSS

D_C

XIN / CLKIN

1

SRS

TSSOP−8

T SUFFIX

CASE 948AL