L2042A-08TT [ALSC]
2.5V LCD Panel Reduction IC; 2.5V的LCD面板减少IC
| 型号： | L2042A-08TT |
| 厂家： | 
ALLIANCE SEMICONDUCTOR CORPORATION |
| 描述： | 2.5V LCD Panel Reduction IC |
| 文件： | 总10页 (文件大小：428K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
October 2003
rev 1.0
L2042A
2.5V LCD Panel Reduction IC
Features
cost savings by reducing the number of circuit board
layers ferrite beads, shielding and other passive
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FCC approved method of EMI attenuation.
Provides up to 15dB of EMI suppression.
Generates a low EMI spread spectrum clock of the
input frequency.
components that are traditionally required to pass EMI
regulations.
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Input frequency range: 30MHz to 75 MHz.
Optimized for 32.5MHz, 54MHz, and 65MHz.
Internal loop filter minimizes external components
and board space.
The L2042A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all digital method.
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Selectable spread deviation.
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. 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’.
SSON# control pin for spread spectrum enable
and disable options.
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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.
§
Applications
Product Description
The L2042A is targeted towards digital flat panel
applications for Notebook PCs, Palm-size PCs, office
automation equipment, and LCD monitors.
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
wide reduction of EMI of down stream clock and data
dependent signals. The L2042A allows significant system
Block Diagram
VDD
DIV2
SR0
CP1 CP0 SSON#
PLL
Modulation
CLKIN
Frequency
Divider
Output
Divider
Phase
Loop
Filter
VCO
Detector
Feedback
Divider
MODOUT
VSS
Alliance Semiconductor
2575, Augustine Drive · Santa Clara, CA · Tel: 408.855.4900 · Fax: 408.855.4999 · www.alsc.com
October 2003
rev 1.0
L2042A
Pin Configuration
1
2
3
4
8
7
6
5
VDD
SR0
XIN /CLK
CP0
L2042A
CP1
VSS
ModOUT
SSON#
Pin Description
Pin#
Pin Name
Type
Description
External reference frequency input. Connect to an externally generated
reference signal.
1
CLKIN
I
Digital logic input used to select charge pump current. Refer Modulation
Selection Table. This pin has an internal pull-up resistor.
2
CP0
I
Digital logic input used to select charge pump current. Refer Modulation
Selection Table. This pin has an internal pull-up resistor.
3
4
CP1
VSS
I
P
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.
6
SSON#
I
7
5
8
ModOUT
SR0
O
I
Spread spectrum clock output.
Digital logic input used to select Spreading Range Refer Modulation
Selection Table. This pin has an internal pull-up resistor.
VDD
P
Power supply for the entire chip (+2.5V or 3.3V)
Modulation Selection Table
Spreading Range (± %)
CP0
CP1
SR0
Modulation Rate
32.5MHz
0.49
1.71
1.2
54MHz
0.92
1.48
0.92
1.48
0.71
1.14
0.4
65MHz
0.88
1.37
0.88
1.37
0.58
0.9
70MHz
0.87
1.32
0.84
1.33
0.42
0.73
0.25
0.37
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1.69
1.09
1.68
0.8
(FIN/40) * 62.49 KHz
0.3
1.29
0.62
0.48
2.5V LCD Panel EMI Reduction IC
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L2042A
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.
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
1
2
8
7
6
5
CLKIN
VDD
SR0
65 MHz from Graphics Accelerator
CP0
CP1
VSS
0.1µF
VDD
3
ModOUT
SSON#
4
Digital control for SS
Enable or Disable
L2042A
2.5V LCD Panel EMI Reduction IC
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October 2003
rev 1.0
L2042A
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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October 2003
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L2042A
Absolute Maximum Ratings
Symbol
Parameter
Rating
-0.5 to + 7.0
-65 to +125
0 to 70
Unit
VDD, VIN
TSTG
Voltage on any pin with respect to GND
Storage temperature
V
°C
°C
TA
Operating temperature
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
VIL
Parameter
Min
GND – 0.3
2.0
Typ
Max
0.8
Unit
V
Input low voltage
Input high voltage
-
-
VIH
VDD + 0.3
V
Input low current (pull-up resistors on inputs SR0, SR1,
CP0 and CP1)
IIL
-
-
-35
µA
IIH
Input high current (pull-down resistor on input SSON#)
Output low voltage (VDD = 3.3V, IOL = 20mA)
Output high voltage (VDD = 3.3V, IOH = 20mA)
-
-
-
-
-
35
0.4
-
µA
V
VOL
VOH
2.5
V
Dynamic supply current normal mode (2.5V, and 15pF
loading)
TBD @
30MHz
TBD
@70MHz
ICC
-
mA
IDD
Static supply current standby mode
Operating voltage
-
0.6
2.85
0.18
50
-
3.7
-
mA
V
VDD
tON
2.25
Power up time (first locked clock cycle after power up)
Clock output impedance
-
-
mS
ZOUT
-
2.5V LCD Panel EMI Reduction IC
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L2042A
AC Electrical Characteristics
Symbol
Parameter
Min Typ Max Unit
fIN
Input frequency
30
30
0.7
0.6
-
-
-
75
75
MHz
MHz
ns
fOUT
Output frequency
tLH
tHL
tJC
tD
*
Output rise time (measured at 0.8V to 2.0V)
Output fall time (measured at 2.0V to 0.8V)
Jitter (cycle to cycle)
0.9
0.8
-
1.1
1.0
360
55
*
ns
ps
Output duty cycle
40
50
%
*tLH and tHL are measured into a capacitive load of 15pF
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L2042A
Package Information
8-Pin SOIC
H
E
D
A2
A
C
q
e
A1
L
B
Symbol Dimensions in inches Dimensions in millimeters
Min
Max
0.071
0.010
0.069
0.020
0.01
Min
1.45
0.10
1.35
0.31
0.10
4.72
3.75
Max
1.80
0.25
1.75
0.51
0.25
5.12
4.15
A
A1
A2
B
0.057
0.004
0.053
0.012
0.004
0.186
0.148
C
D
E
0.202
0.164
e
0.050 BSC
1.27 BSC
H
L
0.224
0.012
0°
0.248
0.028
8°
5.70
0.30
0°
6.30
0.70
8°
è
2.5V LCD Panel EMI Reduction IC
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October 2003
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L2042A
8-Pin TSSOP
H
E
D
A2
A
q
C
e
A1
L
B
Dimensions in inches
Dimensions in millimeters
Symbol
Min
Max
Min
Max
1.10
0.15
1.05
0.30
0.20
3.10
4.50
A
A1
A2
B
0.047
0.002
0.031
0.007
0.004
0.114
0.169
0.006
0.041
0.012
0.008
0.122
0.177
0.05
0.80
0.19
0.09
2.90
4.30
C
D
E
e
0.026 BSC
0.65 BSC
H
L
0.244
0.018
0°
0.260
0.030
8°
6.20
0.45
0°
6.60
0.75
8°
è
2.5V LCD Panel EMI Reduction IC
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October 2003
L2042A
rev 1.0
Ordering Codes
Part Number
L2042A-08ST
L2042A-08SR
L2042A-08TT
L2042A-08TR
Marking
L2042A
L2042A
L2042A
L2042A
Package type
8 PIN SOIC, TUBE
Qty/reel
2,500
Temperature
0°C To 70°C
0°C To 70°C
0°C To 70°C
0°C To 70°C
8-PIN SOIC, TAPE AND REEL
8-PIN TSSOP, TUBE
8-PIN TSSOP, TAPE AND REEL
2,500
2.5V LCD Panel EMI Reduction IC
9 of 10
October 2003
rev 1.0
L2042A
Alliance Semiconductor Corporation
2595, Augustine Drive,
Santa Clara, CA 95054
Tel# 408-855-4900
Copyright © Alliance Semiconductor
All Rights Reserved
Preliminary Information
Part Number: L2042A
Fax: 408-855-4999
Document Version: v1.0
www.alsc.com
© 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).
All sales of Alliance products are made exclusively according to Alliance's Terms and Conditions of Sale. The purchase of
products from Alliance does not convey a license under any patent rights, copyrights; mask works rights, trademarks, or any
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
injury to the user, and the inclusion of 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.
2.5V LCD Panel EMI Reduction IC
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