P2779A Datasheet, PDF (1/7 Pages) Alliance Semiconductor Corporation – Low-Cost Notebook EMI Reduction IC

P2779A
Product Preview
Low-Cost Notebook EMI
Reduction IC
Product Description
The P2779A is a versatile spread spectrum frequency modulator
designed specifically for mobile and digital camera and other digital
video and imaging applications. The P2779A reduces electromagnetic
interference (EMI) at the clock source, which provides system−wide
reduction of EMI of all clock dependent signals. The P2779A allows
significant system cost savings by reducing the number of circuit
board layers and shielding that are traditionally required to pass EMI
regulations.
The P2779A uses the most efficient and optimized modulation
profile approved by the FCC.
The P2779A 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 P2779A is targeted toward mobile 3D graphics chip set
applications.
Features
• Provides up to 15 dB of EMI Suppression
• FCC Approved Method of EMI Attenuation
• Generates a 1X Low EMI Spread Spectrum Clock of the Input
Frequency
• Operates between 20 MHz and 38 MHz Input Frequency Range
• External Loop Filter for Spread Percentage Adjustment
• Spreading Ranges from ±0.25% to ±2.5%
• Ultra Low Cycle−to−Cycle Jitter
• Zero−Cycle Slip at Small Deviations
• 3.3 V Operating Voltage
• Low Power CMOS Design
• Available in 8−pin SOIC and TSSOP Packages
• Available in Industrial Temperature Operating Range
(−40°C to +85°C)
• These are Pb−Free Devices
This document contains information on a product under development. ON Semiconductor
reserves the right to change or discontinue this product without notice.
http://onsemi.com
SOIC−8
S SUFFIX
CASE 751BD
TSSOP−8
T SUFFIX
CASE 948AL
PIN CONFIGURATION
1
XIN / CLKIN
VDD
XOUT
PD
P2779A
REF
ModOUT
LF
VSS
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 7 of this data sheet.
© Semiconductor Components Industries, LLC, 2011
1
August, 2011 − Rev. P2
Publication Order Number:
P2779A/D