© Semiconductor Components Industries, LLC, 2011

August, 2011 − Rev. 3

1

Publication Order Number:

ASM3P2183A/D

ASM3P2183A

EMI Reduction IC

Description

The ASM3P2183A is a versatile spread spectrum frequency

modulator designed specifically for a wide range of input clock

frequencies from 6 MHz to 90 MHz. (Refer to Input Frequency and

Modulation Rate Table). The ASM3P2183A can generate an EMI

reduced clock from an OSC or a system generated clock. The

ASM3P2183A offers a Down Spread clock with a percentage

deviation of −1.25% and a Center Spread clock with a percentage

deviation of

± 0.42%.

The ASM3P2183A reduces electromagnetic interference (EMI) at

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

stream clock and data dependent signals. The ASM3P2183A 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 ASM3P2183A uses the most efficient and optimized

modulation profile approved by the FCC and is implemented in a

proprietary all digital method.

The ASM3P2183A 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.’

Applications

The ASM3P2183A 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

Frequency

Space

Applications

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 6 of this data sheet.

ORDERING INFORMATION

FS1

FS0

ModOUT

XOUT

XIN / CLKIN

1

SS%

TSSOP−8

T SUFFIX

CASE 948AL