L2042A-08SR ALSC [Alliance Semiconductor Corporation], L2042A-08SR Datasheet

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L2042A-08SR

Manufacturer Part Number
L2042A-08SR
Description
2.5V LCD Panel Reduction IC
Manufacturer
ALSC [Alliance Semiconductor Corporation]
Datasheet
CLKIN
October 2003
rev 1.0
Features
Product Description
The L2042A is a versatile spread spectrum frequency
modulator designed specifically for digital falt panel
applications.
interference (EMI) at the clock source, allowing system
wide reduction of EMI of down stream clock and data
dependent signals. The L2042A allows significant system
Block Diagram
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2575, Augustine Drive
FCC approved method of EMI attenuation.
Provides up to 15dB of EMI suppression.
Generates a low EMI spread spectrum clock of the
input frequency.
Input frequency range: 30MHz to 75 MHz.
Optimized for 32.5MHz, 54MHz, and 65MHz.
Internal loop filter minimizes external components
and board space.
Selectable spread deviation.
SSON# control pin for spread spectrum enable
and disable options.
Low cycle-to-cycle jitter.
2.5V or 3.3V operating voltage range.
TTL or CMOS compatible outputs.
Ultra-low power CMOS design.
Supports most mobile graphic accelerator and
LCD timing controller specifications.
Available in 8-pin SOIC and TSSOP.
The
L2042A
reduces
Santa Clara, CA
Frequency
Feedback
Divider
Divider
electromagnetic
2.5V LCD Panel Reduction IC
SR0
Alliance Semiconductor
Modulation
Detector
CP1
Phase
CP0
Tel: 408.855.4900
SSON#
cost savings by reducing the number of circuit board
layers ferrite beads,
components that are traditionally required to pass EMI
regulations.
The L2042A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all digital method.
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 L2042A is targeted towards digital flat panel
applications for Notebook PCs, Palm -size PCs, office
automation equipment, and LCD monitors.
The L2042A modulates the output of a single PLL in
VDD
Loop
Filter
Fax: 408.855.4999
VSS
VCO
PLL
shielding and other passive
Divider
Output
www.alsc.com
DIV2
L2042A
MODOUT

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L2042A-08SR Summary of contents

Page 1

... The L2042A uses the most efficient and optimized modulation profile approved by the FCC and is implemented in a proprietary all digital method. The L2042A 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 ...

Page 2

... Digital logic input used to select Spreading Range Refer Modulation Selection Table. This pin has an internal pull-up resistor. Power supply for the entire chip (+2.5V or 3.3V) Spreading Range ( %) 54MHz 65MHz 0.92 0.88 1.48 1.37 0.92 0.88 1.48 1.37 0.71 0.58 1.14 0.9 0.4 0.3 0.62 0.48 2.5V LCD Panel EMI Reduction IC L2042A VDD SR0 ModOUT SSON# Modulation Rate 70MHz 0.87 1.32 0.84 1.33 (F /40) * 62.49 KHz IN 0.42 0.73 0.25 0. ...

Page 3

... CLKIN, Pin1). Example: The L2042A is designed for high-resolution flat panel applications and is able to support panel frequencies from MHz. For a 65MHz pixel clock frequency, a spreading selection of CP0=0 and CP1=1 and SR0=1 gives a percentage deviation of TBD%. Refer Modulation Selection Table. This results in frequency on ModOUT being swept from TBD to TBD MHz ...

Page 4

... EMC software has already been characterized to correlate with the electrical characteristics of Alliance EMI reduction ICs. The figure below is an illustration of this simulation result. Please visit our website at www.alsc.com EMI-Lator ®. for information on how to obtain a free copy and demonstration of Simulation results From EMI-Lator® 2.5V LCD Panel EMI Reduction IC L2042A ...

Page 5

... Static supply current standby mode DD V Operating voltage DD t Power up time (first locked clock cycle after power up Clock output impedance OUT Rating -0 7.0 -65 to +125 3.3V 20mA 3.3V 20mA) OH 2.5V LCD Panel EMI Reduction IC L2042A Unit V °C °C Min Typ Max GND – 0.3 - 0 ...

Page 6

... Output rise time (measured at 0.8V to 2.0V Output fall time (measured at 2.0V to 0.8V Jitter (cycle to cycle Output duty cycle D *t and t are measured into a capacitive load of 15pF LH HL Parameter 2.5V LCD Panel EMI Reduction IC L2042A Min Typ Max Unit MHz MHz 0.7 0.9 1.1 ns 0.6 0.8 1 ...

Page 7

... Min Max A 0.057 0.071 A1 0.004 0.010 A2 0.053 0.069 B 0.012 0.020 C 0.004 0.01 D 0.186 0.202 E 0.148 0.164 e 0.050 0.224 0.248 L 0.012 0.028 è 0° 8° 8-Pin SOIC Min Max 1.45 1.80 0.10 0.25 1.35 1.75 0.31 0.51 0.10 0.25 4.72 5.12 3.75 4.15 1.27 BSC 5.70 6.30 0.30 0.70 0° 8° 2.5V LCD Panel EMI Reduction IC L2042A ...

Page 8

... A1 0.002 0.006 A2 0.031 0.041 B 0.007 0.012 C 0.004 0.008 D 0.114 0.122 E 0.169 0.177 e 0.026 BSC H 0.244 0.260 L 0.018 0.030 è 0° 8-Pin TSSOP Dimensions in millimeters Min Max 1.10 0.05 0.15 0.80 1.05 0.19 0.30 0.09 0.20 2.90 3.10 4.30 4.50 0.65 BSC 6.20 6.60 0.45 0.75 8° 0° 8° 2.5V LCD Panel EMI Reduction IC L2042A ...

Page 9

... October 2003 rev 1.0 Ordering Codes Part Number Marking L2042A-08ST L2042A L2042A-08SR L2042A L2042A-08TT L2042A L2042A-08TR L2042A Package type 8 PIN SOIC, TUBE 8-PIN SOIC, TAPE AND REEL 8-PIN TSSOP, TUBE 8-PIN TSSOP, TAPE AND REEL 2.5V LCD Panel EMI Reduction IC L2042A Qty/reel Temperature ...

Page 10

... Alliance products in such life-supporting systems implies that the manufacturer assumes all risk of such use and agrees to indemnify Alliance against all claims arising from such use. Copyright © Alliance Semiconductor All Rights Reserved Preliminary Information Part Number: L2042A Document Version: v1.0 2.5V LCD Panel EMI Reduction IC L2042A ...

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