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| November 2003 rev 1.0 ASM3P2531A Features FCC approved method of EMI attenuation. Generates a low EMI spread spectrum of the input clock frequency. Optimized for input frequency range between 35MHz - 55MHz. Internal loop filter minimizes external components and board space. Frequency Deviation: 1.65%. Low inherent cycle-to-cycle jitter. 3.3 V or 5 V operating voltage. CMOS/TTL compatible inputs and outputs. Ultra low power CMOS design: 5.50 mA @3.3 V. Supports notebook VGA and other LCD timing controller applications. Available in 8-pin SOIC and TSSOP. dependent signals. It allows significant system cost savings by reducing the number of circuit board layers and shielding traditionally required to pass EMI regulations. The ASM3P2531A modulates the output of a single PLL in order to spread the bandwidth of a synthesized clock, thereby decreasing 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 clock generators. Lowering EMI by increasing a signal's bandwidth is called spread spectrum clock generation. The ASM3P2531A uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all-digital method. Product Description The ASM3P2531A is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. It reduces electromagnetic interference (EMI) at the clock source allowing systemwide reduction of EMI of downstream clock and data Applications The ASM3P2531A is targeted toward the notebook VGA chip and other displays using an LVDS interface, PC peripheral devices, and embedded systems Block Diagram STOP VDD Modulation CLKIN Crystal Oscillator PLL Frequency Divider Feedback Divider Phase Detector Loop Filter VCO Output Divider MODOUT VSS Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 1 of 8 November 2003 rev 1.0 Pin Configuration ASM3P2531A CLKIN VDD VSS ModOUT 1 2 3 4 ASM3P2531A 8 7 6 5 NC NC NC STOP Spread Range Selection, VDD = 3.3 V CLKIN frequency 35 MHz - 55 MHz Pin Description Pin# 1 2 3 4 5 6 7 8 Pin Name CLKIN VDD VSS ModOUT STOP NC NC NC Type I P P O I External reference frequency input. Power supply for the entire chip. Ground to entire chip. Spread spectrum clock output or reference output. Refer Standby Mode Selection. Active LOW signal. When HIGH, enables ModOUT and when LOW, ModOUT would be LOW. No connect. No connect. No connect. Description Spreading range 1.65% Modulation rate (CLKIN/1280) KHz Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 2 of 8 November 2003 rev 1.0 Schematic for a Typical Application ASM3P2531A Input clock 35MHz - 55MHz 0.1F Ferrite Bead VDD 1 2 ASM3P3531A CLKIN NC 8 VDD NC 7 3 VSS NC 6 VDD 0 4 ModOUT EMI reduced clock output 35MHz - 55MHz STOP 5 0 Use either pull-up or pulldown resistors with 0 Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 3 of 8 November 2003 rev 1.0 Absolute Maximum Ratings Symbol VDD, VIN TSTG TA Parameter Voltage on any pin with respect to GND Storage temperature Operating temperature Rating -0.5 to +7.0 -65 to +125 0 to +70 ASM3P2531A Unit V C C DC Electrical Characteristics Symbol VIL VIH IIL IIH VOL VOH IDD ICC VDD tON ZOUT Input low voltage Input high voltage Input low current Input high current Output low voltage Output high voltage VDD = 3.3 V, IOL = 20 mA VDD = 5.0 V, IOL = 20 mA VDD = 3.3 V, IOL = 20 mA VDD = 5.0 V, IOL = 20 mA Normal mode Dynamic supply current Operating voltage Power-up time (first locked cycle after power up) Clock output impedance 3.3 V and 10 pF loading 5.0 V and 10 pF loading 2.5 4.5 0.6 fIN-min 3.2 6.2 2.7 3.3 0.18 50 fIN-typ fIN-max 7.0 13.6 5.5 mA mA V mS Parameter Min GND - 0.3 2.0 Typ Max 0.8 VDD + 0.3 -35 35 0.4 Unit V V A A V V V V mA Static supply current standby mode AC Electrical Characteristics Symbol fIN fOUT tLH 1 tHL 1 tJC TD Input frequency Output frequency Output rise time Output fall time Jitter (cycle to cycle) Output duty cycle 45 50 Measured at 0.8 V to 2.0 V Measured at 1.2 V to 3.75 V Measured at 2.0 V to 0.8 V Measured at 1.2 V to 3.75 V 0.6 Parameter Min 35 35 0.7 0.9 0.75 0.8 0.75 360 55 1.0 Typ Max 55 55 1.1 Unit MHz MHz ns ns ns ns ps % Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 4 of 8 November 2003 rev 1.0 ASM3P2531A Package Information 8-Pin SOIC Symbol Dimensions in inches Min Max 0.069 0.010 0.022 0.012 0.197 0.158 0.244 Dimensions in millimeters Min 1.35 0.10 0.33 0.18 4.78 3.80 5.80 1.27 BSC 0.40 0 0.89 8 Max 1.75 0.25 0.53 0.27 5.00 4.01 6.20 A A1 B C D E H e L 0.053 0.004 0.013 0.007 0.188 0.150 0.228 0.050 BSC 0.016 0 0.035 8 Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 5 of 8 November 2003 rev 1.0 Package Information ASM3P2531A 8-Pin TSSOP Symbol A A1 A2 B C D H E e L Dimensions in inches Min 0.002 0.033 0.008 0.004 0.114 0.169 0.020 0 Max 0.043 0.006 0.037 0.012 0.008 0.122 0.177 0.028 8 Dimensions in millimeters Min 0.05 0.85 0.19 0.09 2.90 6.40 BSC 4.30 0.65 BSC 0.50 0 0.70 8 4.50 Max 1.10 0.15 0.95 0.30 0.20 3.10 0.252 BSC 0.026 BSC Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 6 of 8 November 2003 rev 1.0 ASM3P2531A Ordering Information Ordering Code ASM3P2531A-08ST ASM3P2531A-08SR ASM3I2531A-08ST ASM3I2531A-08SR ASM3P2531A-08TT ASM3P2531A-08TR ASM3I2531A-08TT ASM3I2531A-08TR Package Type 8-pin 150mil SOIC -TUBE 8-pin 150-mil SOIC -TAPE & REEL 8-pin 150mil SOIC -TUBE 8-pin 150-mil SOIC -TAPE & REEL 8-pin 4.4mm TSSOP -TUBE 8-pin 4.4mm TSSOP -TAPE & REEL 8-pin 4.4mm TSSOP -TUBE 8-pin 4.4mm TSSOP - TAPE & REEL Operating Range Commercial Commercial Industrial Industrial Commercial Commercial Industrial Industrial Ordering Information OR - SOT23/T/R TT - TSSOP, TUBE TR - TSSOP, T/R VT - TVSOP, TUBE VR - TVSOP, T/R ST - SOIC, TUBE SR - SOIC, T/R QR - QFN, T/R QT - QFN, TUBE BT - BGA, TUBE BR - BGA, T/R ASM3P2531A-08TR PIN COUNT PART NUMBER X = Automotive I = Industrial P or n/c = Commercial 1 - reserved 2 - Non PLL based 3 - EMI Reduction 4 - DDR support products 5 - STD Zero Delay Buffer 6 - power management 7 - power management 8 - power management 9 - Hi performance 0 - reserved Alliance Semiconductor Mixed Signal Product Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 7 of 8 November 2003 rev 1.0 ASM3P2531A Alliance Semiconductor Corporation 2595, Augustine Drive, Santa Clara, CA 95054 Tel# 408-855-4900 Fax: 408-855-4999 www.alsc.com Copyright (c) Alliance Semiconductor All Rights Reserved Preliminary Information Part Number: ASM3P2531A Document Version: v1.0 (c) 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. Low Frequency EMI Reduction Notice: The information in this document is subject to change without notice. 8 of 8 |
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