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 2 of 10 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 3 of 10 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 4 of 10 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 - 5 of 10 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 6 of 10 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 7 of 10 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 8 of 10 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 9 of 10 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. 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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 10 of 10