ALSC L2042A-08TT 2.5v lcd panel reduction ic Datasheet

L2042A
October 2003
rev 1.0
2.5V LCD Panel Reduction IC
Features
§
cost savings by reducing the number of circuit board
§
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.
The L2042A uses the most efficient and optimized
modulation profile approved by the FCC and is
§
Internal loop filter minimizes external components
and board space.
implemented in a proprietary all digital method.
§
Selectable spread deviation.
§
SSON# control pin for spread spectrum enable
and disable options.
§
Low cycle-to-cycle jitter.
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
§
2.5V or 3.3V operating voltage range.
TTL or CMOS compatible outputs.
§
Ultra-low power CMOS design.
by oscillators and most frequency generators. Lowering
EMI by increasing a signal’s bandwidth is called ‘spread
§
Supports most mobile graphic accelerator and
LCD timing controller specifications.
spectrum clock generation’.
§
Available in 8-pin SOIC and TSSOP.
Applications
layers ferrite beads,
shielding and other passive
components that are traditionally required to pass EMI
regulations.
The L2042A modulates the output of a single PLL in
Product Description
The L2042A is a versatile spread spectrum frequency
modulator designed specifically for digital falt panel
applications. The L2042A reduces electromagnetic
interference (EMI) at the clock source, allowing system
order to “spread” the bandwidth of a synthesized clock,
The L2042A is targeted towards digital flat panel
applications for Notebook PCs, Palm -size PCs, office
automation equipment, and LCD monitors.
wide reduction of EMI of down stream clock and data
dependent signals. The L2042A allows significant system
Block Diagram
SR0
CP1 CP0 SSON#
VDD
DIV2
PLL
Modulation
CLKIN
Frequency
Divider
Feedback
Divider
Phase
Detector
Loop
Filter
VCO
Output
Divider
MODOUT
VSS
Alliance Semiconductor
2575, Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com
L2042A
October 2003
rev 1.0
Pin Configuration
XIN /CLK
CP0
8
VDD
7
SR0
1
2
L2042A
CP1
3
6
ModOUT
VSS
4
5
SSON#
Pin Description
Pin#
Pin Name
Type
1
CLK IN
I
2
CP0
I
3
CP1
I
4
VSS
P
6
SSON#
I
7
ModOUT
O
5
SR0
I
8
VDD
P
Description
External reference frequency input. Connect to an externally generated
reference signal.
Digital logic input used to select charge pump current. Refer Modulation
Selection Table. This pin has an internal pull-up resistor.
Digital logic input used to select charge pump current. Refer Modulation
Selection Table. This pin has an internal pull-up resistor.
Ground to entire chip. Connect to system ground.
Digital logic input used to enable Spread Spectrum function (Active LOW).
Spread Spectrum function enabled when LOW, disabled when HIGH. This
pin has an internal pull-low resistor.
Spread spectrum clock output.
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)
Modulation Selection Table
CP0
CP1
SR0
0
0
0
Spreading Range (± %)
32.5MHz
54MHz
65MHz
70MHz
0
0.49
0.92
0.88
0.87
0
1
1.71
1.48
1.37
1.32
0
1
0
1.2
0.92
0.88
0.84
0
1
1
1.69
1.48
1.37
1.33
1
0
0
1.09
0.71
0.58
0.42
1
0
1
1.68
1.14
0.9
0.73
1
1
0
0.8
0.4
0.3
0.25
1
1
1
1.29
0.62
0.48
0.37
2.5V LCD Panel EMI Reduction IC
Modulation Rate
(FIN /40) * 62.49 KHz
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L2042A
October 2003
rev 1.0
Spread Spectrum
The Modulation Selection Table 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 CLKIN, Pin1).
Example:
The L2042A is designed for high-resolution flat panel applications and is able to support panel frequencies from
30 to 75 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. This particular example (See figure below) given here is a common EMI reduction
method for notebook LCD panel and has already been implemented by most of the leading OEM and mobile
graphic accelerator manufacturers.
65 MHz from Graphics Accelerator
1 CLKIN
VDD
8
2
CP0
SR0
7
3
CP1
ModOUT
6
4
VSS
SSON#
Modulated 65MHz signal
with 1.5% deviation and
modulation rate of
50.77KHz. This signal is
connected back to the
spread spectrum input pin
(SSIN) of the graphics
accelerator
0.1µF
VDD
5
L2042A
2.5V LCD Panel EMI Reduction IC
Digital control for SS
Enable or Disable
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L2042A
October 2003
rev 1.0
EMC Software Simulation
By using Alliance’s proprietary EMC simulation software – EMI-Lator®, radiated system level EMI analysis can
be made easier, allowing quantitative measure on the benefits of Alliance’s EMI reduction products. The
simulation engine of this 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 for information on how to obtain a free copy and demonstration of
EMI-Lator ®.
Simulation results From EMI-Lator®
2.5V LCD Panel EMI Reduction IC
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L2042A
October 2003
rev 1.0
Absolute Maximum Ratings
Symbol
VDD , VIN
Parameter
Voltage on any pin with respect to GND
Rating
Unit
-0.5 to + 7.0
V
TSTG
Storage temperature
-65 to +125
°C
TA
Operating temperature
0 to 70
°C
Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum
ratings for extended periods may affect device reliability.
DC Electrical Characteristics
Symbol
Parameter
Min
Typ
Max
Unit
GND – 0.3
-
0.8
V
2.0
-
VDD + 0.3
V
-
-
-35
µA
-
-
35
µA
-
-
0.4
V
2.5
TBD @
30MHz
-
-
V
mA
0.6
TBD
@70MHz
-
2.25
2.85
3.7
V
mS
VIL
Input low voltage
VIH
IIH
Input high voltage
Input low current (pull-up resistors on inputs SR0, SR1,
CP0 and CP1)
Input high current (pull-down resistor on input SSON#)
VOL
Output low voltage (V DD = 3.3V, IOL = 20mA)
VOH
IDD
Output high voltage (V DD = 3.3V, IOH = 20mA)
Dynamic supply current normal mode (2.5V, and 15pF
loading)
Static supply current standby mode
VDD
Operating voltage
tON
Power up time (first locked clock cycle after power up)
-
0.18
-
ZOUT
Clock output impedance
-
50
-
IIL
ICC
2.5V LCD Panel EMI Reduction IC
-
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mA
L2042A
October 2003
rev 1.0
AC Electrical Characteristics
Symbol
Parameter
Min
Typ
Max
Unit
fIN
Input frequency
30
-
75
MHz
fOUT
Output frequency
30
-
75
MHz
tLH *
Output rise time (measured at 0.8V to 2.0V)
0.7
0.9
1.1
ns
tHL*
Output fall time (measured at 2.0V to 0.8V)
0.6
0.8
1.0
ns
tJC
Jitter (cycle to cycle)
-
-
360
ps
tD
Output duty cycle
40
50
55
%
*tLH and tHL are measured into a capacitive load of 15pF
2.5V LCD Panel EMI Reduction IC
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L2042A
October 2003
rev 1.0
Package Information
8-Pin SOIC
H
E
D
A2
A
C
A1
D
θ
e
L
B
Symbol
Dimensions in inches Dimensions in millimeters
Min
Max
Min
Max
A
0.057
0.071
1.45
1.80
A1
0.004
0.010
0.10
0.25
A2
0.053
0.069
1.35
1.75
B
0.012
0.020
0.31
0.51
C
0.004
0.01
0.10
0.25
D
0.186
0.202
4.72
5.12
E
0.148
0.164
3.75
4.15
e
0.050 BS C
1.27 BSC
H
0.224
0.248
5.70
6.30
L
0.012
0.028
0.30
0.70
è
0°
8°
0°
8°
2.5V LCD Panel EMI Reduction IC
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L2042A
October 2003
rev 1.0
8-Pin TSSOP
H
E
D
A2
A
e
θ
C
A1
L
B
Dimensions in inches
Symbol
Min
A
0.047
A1
0.002
0.006
0.05
0.15
A2
0.031
0.041
0.80
1.05
B
0.007
0.012
0.19
0.30
C
0.004
0.008
0.09
0.20
D
0.114
0.122
2.90
3.10
E
0.169
0.177
4.30
4.50
e
Max
Dimensions in millimeters
Min
Max
1.10
0.026 BSC
0.65 BSC
H
0.244
0.260
6.20
6.60
L
0.018
0.030
0.45
0.75
è
0°
8°
0°
8°
2.5V LCD Panel EMI Reduction IC
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L2042A
October 2003
rev 1.0
Ordering Codes
Part Number
Marking
Package type
L2042A-08ST
L2042A
8 PIN SOIC, TUBE
L2042A-08SR
L2042A
8-PIN SOIC, TAPE AND REEL
L2042A-08TT
L2042A
8-PIN TSSOP, TUBE
L2042A-08TR
L2042A
8-PIN TSSOP, TAPE AND REEL
2.5V LCD Panel EMI Reduction IC
Qty/reel
Temperature
0 °C To 70 ° C
2,500
0 °C To 70 ° C
0 °C To 70 ° C
2,500
0 °C To 70 ° C
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L2042A
October 2003
rev 1.0
Alliance Semiconductor Corporation
2595, Augustine Drive,
Santa Clara, CA 95054
Tel# 408-855-4900
Fax: 408-855-4999
www.alsc.com
Copyright © Alliance Semiconductor
All Rights Reserved
Preliminary Information
Part Number: L2042A
Document Version: v1.0
© Copyright 2003 Alliance Semiconductor Corporation. All rights reserved. Our three-point logo, our name and Intelliwatt are
trademarks or registered trademarks of Alliance. All other brand and product names may be the trademarks of their
respective companies. Alliance reserves the right to make changes to this document and its products at any time without
notice. Alliance assumes no responsibility for any errors that may appear in this document. The data contained herein
represents Alliance's best data and/or estimates at the time of issuance. Alliance reserves the right to change or correct this
data at any time, without notice. If the product described herein is under development, significant changes to these
specifications are possible. The information in this product data sheet is intended to be general descriptive information for
potential customers and users, and is not intended to operate as, or provide, any guarantee or warrantee to any user or
customer. Alliance does not assume any responsibility or liability arising out of the application or use of any product
described herein, and disclaims any express or implied warranties related to the sale and/or use of Alliance products
including liability or warranties related to fitness for a particular purpose, merchantability, or infringement of any intellectual
property rights, except as express agreed to in Alliance's Terms and Conditions of Sale (which are available from Alliance).
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other intellectual property rights of Alliance or third parties. Alliance does not authorize its products for use as critical
components in life-supporting systems where a malfunction or failure may reasonably be expected to result in significant
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assumes all risk of such use and agrees to indemnify Alliance against all claims arising from such use.
2.5V LCD Panel EMI Reduction IC
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