December 2004 ASM3P2853A rev 0.7 Peak EMI Reducing Solution Features shielding that are required to pass EMI regulations. The Generates an EMI optimized clock signal at ASM3P2853A modulates the output of PLL in order to output. spread the bandwidth of a synthesized clock, thereby Input frequency: 25 MHz. decreasing the peak amplitudes of its harmonics. This Frequency outputs: results in significantly lower system EMI compared to the o USB Clock (48 MHz unmodulated) typical narrow band signal produced by oscillators and o 50 MHz (modulated), ±1% centre spread most clock generators. Lowering EMI by increasing a Modulation rate: 39 KHz. signal’s bandwidth is called spread spectrum clock Spread Spectrum ON/OFF control generation. Supply voltage range 2.5V ± 5%. Available in 8-pin SOIC package. Applications Commercial Temperature range. ASM3P2853A is targeted towards EMI management for Product Description high speed digital applications such as PC peripheral The ASM3P2853A is a versatile spread spectrum devices, consumer electronics and embedded controller frequency systems. modulator. The ASM3P2853A reduces electromagnetic interference (EMI) at the clock source. The ASM3P2853A allows significant system cost savings by reducing the number of circuit board layers and Block Diagram VDD XIN XOUT Crystal Oscillator SSONB PWDNB PLL1 USB Clock (48 MHz Unmodulated) PLL2 50 MHz Modulated VSS Alliance Semiconductor 2575 Augustine Drive • Santa Clara CA • Tel: 408-855-4900 • Fax: 408-855-4999 • www.alsc.com ASM3P2853A December 2004 rev 0.7 Pin Configuration 8 50 MHz 7 USB Clock 3 6 SSONB 4 5 PWDNB XIN 1 XOUT 2 VDD VSS ASM3P2853A Pin Description Pin Name Type XIN I Description Connection to crystal or external reference frequency input. This pin has dual functions. It can be connected either to an external crystal or an external reference clock. Connection to crystal. If using an external reference clock, this pin must be left XOUT O VDD P Power supply for the analog and digital blocks VSS P Ground to entire chip. PWDNB I SSONB I USB Clock O Clock output -1 (48 MHz unmodulated) 50 MHz O Clock output -2 (50 MHz modulated) unconnected. Power-down control pin. Pull low to enable the power-down mode. Connect to VDD, if not used. Digital logic input used to enable spread spectrum function (Active LOW). Spread spectrum is enabled when LOW, disabled when HIGH. Peak EMI Reducing Solution 2 of 8 ASM3P2853A December 2004 rev 0.7 Absolute Maximum Ratings Symbol VDD Parameter Rating Supply voltage, DC Unit (VSS – 0.5) to 7 V VI Input voltage, DC (VSS-0.5) to (VDD+0.5) V VO Output voltage, DC (VSS-0.5) to (VDD + 0.5) V IIK Input clamp current (VI<0 or VI>VDD) -50 to +50 mA IOK Output clamp current (VI<0 or VI>VDD) -50 to +50 mA TJ Junction temperature 150 °C Lead temperature (soldering 10 sec) 260 °C 2 kV Input static discharge voltage protection (MIL –STD 883E, Method 3015.7) Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. Operating Conditions Parameter Symbol Supply Voltage VDD Ambient Operating TA Condition / Description 2.5V ± 5% Min Typ Max Unit 2.375 2.5 2.625 V 0 - +70 °C Temperature Range Crystal Resonator Frequency Output Driver Load FXIN 25 CL - - MHz 15 pF Capacitance Crystal Specifications Fundamental AT cut parallel resonant crystal Nominal frequency 25 MHz Frequency tolerance ± 50 ppm or better at 25°C Operating temperature range -25°C to +85°C Storage temperature -40°C to +85°C Load capacitance 18pF Shunt capacitance 7pF maximum ESR 25 Peak EMI Reducing Solution 3 of 8 ASM3P2853A December 2004 rev 0.7 DC Electrical Characteristics Parameter Symbol Conditions / Description Min Typ Max Unit IDD VDD=2.5V, FXIN=25MHz, CL=15pF 15 20 25 mA - 1.5 - mA Overall Supply Current, Dynamic Supply Current, Static IDDL VDD = 2.5V, XIN = 0, PWDNB =0 All input pins High-Level Input Voltage Low-Level Input Voltage High-Level Input Current Low-Level Input Current (pull-up) VIH VDD=2.5V 1.7 - - V VIL VDD=2.5V - - 0.7 V IIH - - 25 µA IIL - - -25 µA Clock Outputs High-Level Output Source Current Low-Level Output Sink Current High-Level Output Source Current Low-Level Output Sink Current Output Impedance IxOH VDD= 2.5V ,V(XIN) = 0, VO=2V -10 -12 -15 mA IxOL VDD= V(XIN) =2.5V, VO=0.4V 10 12 15 mA IOH VO=2V - 8 - mA IOL VO=0.4V - 8 - mA - 42 - ZO Peak EMI Reducing Solution 4 of 8 ASM3P2853A December 2004 rev 0.7 AC Electrical Characteristics Parameter Symbol Conditions/ Description Min Typ Max Unit - 2 - nS - 1.2 - nS tjc - - 200 pS tp - 175 - pS 45 50 55 % Measured from 20% to 80% of the signal Rise Time* tr level Measured from 80% to 20% of the signal Fall Time* tf level Jitter (Cycle to Cycle) Jitter (Period) Clock Duty Cycle Ratio of pulse width (as measured from td rising edge to next falling edge at VDD/2) to one clock period * CL = 15 pF, Input clock frequency = 25 MHz Peak EMI Reducing Solution 5 of 8 ASM3P2853A December 2004 rev 0.7 Package Information 8-Pin SOIC package H E D A2 A A1 D C e L B Dimensions Symbol Inches Millimeters Min Max Min Max A1 0.004 0.010 0.10 0.25 A 0.053 0.069 1.35 1.75 A2 0.049 0.059 1.25 1.50 B 0.012 0.020 0.31 0.51 C 0.007 0.010 0.18 0.25 D 0.193 BSC 4.90 BSC E 0.154 BSC 3.91 BSC e 0.050 BSC 1.27 BSC H 0.236 BSC 6.00 BSC L 0.016 0.050 0.41 1.27 O 0° 8° 0° 8° Peak EMI Reducing Solution 6 of 8 ASM3P2853A December 2004 rev 0.7 Ordering Codes Part number Package Configuration Temperature Range ASM3P2853AF-08-ST 8-pin SOIC ,TUBE Commercial ASM3P2853AF-08-SR 8-pin SOIC, TAPE & REEL Commercial Ordering Information A S M 3 P 2 8 5 3 A F - 0 8 - S R OR - SOT23/T/R TT - TSSOP, TUBE TR – TSSOP, T/R QT – QFN, TUBE BT – BGA, TUBE BR – BGA, T/R ST – SOIC, TUBE SR – SOIC, T/R QR – QFN, T/R VT – TVSOP, TUBE VR – TVSOP, T/R JR – SSOP, T/R JT – SSOP, TUBE PIN COUNT Pb FREE PART NUMBER X = Automotive (-40C to +125C) I = Industrial (-40C to +85C) 1 – reserved 2 - Non PLL based 3 – EMI Reduction 4 – DDR support products P or n/c = Commercial (0C to +70C) 6 – power management 7 – power management 8 – power management 9 – Hi performance Alliance Semiconductor Mixed Signal Product Licensed under US patent #5,488,627, #6,646,463 and #5,631,920. Peak EMI Reducing Solution 7 of 8 ASM3P2853A December 2004 rev 0.7 Alliance Semiconductor Corporation 2575, 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: ASM3P2853A Document Version: v0.7 Note: This product utilizes US Patent # 6,646,463 Impedance Emulator Patent issued to Alliance Semiconductor, dated 11-11-2003 © 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. Peak EMI Reducing Solution 8 of 8