P2041A ALSC | Alldatasheet
Document overview
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Technical content
Features
FCC approved method of EMI attenuation Provides up to 20 dB of EMI suppression Generates a low EMI spread spectrum clock of the input frequency Optimized for 25 MHz to 60MHz input frequency range Internal loop filter minimizes external components and board space 4 selectable spread ranges SSON control pin for spread spectrum enable and disable options Characterizes to work with EMI-Lator®, EMC simulation program. Low cycle-to-cycle jitter 3.3 V or 5.0 V operating range 16 mA output drives TTL or CMOS compatible outputs Low power CMOS design Available in 8 pin SOIC and TSSOP Product Description The P2041 is a selectable spread spectrum frequency modulator designed specifically for PC peripheral and embedded controller markets .The P2041 reduces electromagnetic interference (EMI) at the clock source which provides system wide reduction of EMI of all clock dependent signals. The P2041 allows significant system cost savings by reducing the number of circuit board layers and shielding that are traditionally required to pass EMI regulations. The P2041 uses the most efficient and optimized modulation profile approved by the FCC and is implemented in a proprietary all-digital method. The P2041 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”.
Applications
The P2041 is targeted towards the embedded controller market and PC peripheral markets including scanners, MFP’s, printers, PDA, IA , and GPS devices. Block Diagram
Versatile EMI Reduction IC 2 of 9 Notice: The information in this document is subject to change without notice. Pin Configuration Pin Description Pin# Pin Name Type Description 1 XIN/CLK I Connect to crystal or externally generated clock signal. 2 XOUT I Connect to crystal. No connect if externally generated clock signal is used. 3 SR1 I Digital logic input used to select Spreading Range (see Table 1). This pin has an internal pull-up resistor. 4 VSS P Ground Connection. C onnect to system ground. SSON I Digital logic input used to enable Spread Spectrum function (Active Low). Spread Spectrum function enable when low. This pin has an internal pull- low resistor. 6 ModOUT O Spread Spectrum Clock Output. 7 SR0 I Digital logic input used to select Spreading Range (see Table 1). This pin has an internal pull-up resistor. 8 VDD P Connect to +3.3V or +5.0V Table 1 - Spread Range Selection FS0 SR0 Spreading Range Input Frequency Modulation rate
Versatile EMI Reduction IC 3 of 9 Notice: The information in this document is subject to change without notice. Spread spectrum selection Table 1 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, Pin 1). Example of a typical printer or scanner application that operates on a clock frequency of 40 MHz: A spreading selection of SR1=1 and SR0=1 provides a per centage deviation of +/-1.00%* (see Table 1) of F cen. This results in the frequency on ModOUT being swept from 40.40 MHz to 39.60 MHz at a modulation rate of 40/40*34.72=34.72 KHz (see Table 1). This particular example (see Figure below) given here is a common EMI reduction method for scanners and has already been implemented by most of the leading manufacturers. NOTE: Spreading range selection varies from different system manufac turers and their designs. The spreading range of P2041 can be se t to +/-2.5% when working with certain scanner model.
Versatile EMI Reduction IC 4 of 9 Notice: The information in this document is subject to change without notice. EMC Software Simulation By using Alliance Semiconductor’s proprietary EMC simulation software – EMI-lator®, radiated system level EMI analysis can be made easier to allow a quantitative assessment on 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 IC’s. The figur e below is an example of the simulation result. Please visit our web site at www.alsc.com for information on how to obtain a free copy and demonstration of EMI-lator®. Simulation Result from EMI-lator®
Versatile EMI Reduction IC 5 of 9 Notice: The information in this document is subject to change without notice. Absolute Maximum Ratings Symbol Parameter Rating Unit VDD, VIN Voltage on any pin with respect to GND -0.5 to + 7.0 V TSTG Storage temperature -65 to +125 °C TA Operating temperature 0 to +70 °C Symbol Parameter Min Typ Max Unit VIL Input Low Voltage GND – 0.3 - 0.8 V VIH Input High Voltage 2.0 - VDD + 0.3 V IIL Input Low Current (pull-up resistor on inputs SR0, 1) - - -35 µA IIH Input High Current (pull-down resistor on input SSON) - - 35 µA IXOL XOUT Output Low Current (@ 0.4V, VDD = 3.3V) - 3 - mA IXOH XOUT Output High Current (@ 2.5V, VDD = 3.3V) - 3 - mA VOL Output Low Voltage (VDD=3.3V, IOL = 20 mA) - - 0.4 V VOH Output High Voltage (VDD=3.3V, IOH = 20 mA) 2.5 - - V IDD Static Supply Current - 0.6 - mA ICC Dynamic Supply Current (3.3V and 15 pF loading) 7 8.6 10 mA VDD Operating Voltage 2.7 3.3 5.5 V Symbol Parameter Min Typ Max Unit fIN Input Frequency when 25 40 60 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 0.8V to 2.0V) 0.6 0.8 1.0 ns tJC Jitter (cycle to cycle) - - 360 ps tD Output duty cycle 45 50 55 % *tLH and tHL are measured into a capacitive load of 15pF
Versatile EMI Reduction IC 6 of 9 Notice: The information in this document is subject to change without notice.
Package Information
Mechanical Package Outline 8-Pin SOIC Dimensions in inches Dimensions in millimeters Symbol Min Nor Max Min Nor Max e 0.050 BSC 1.27 BSC Note: Controlling dimensions are millimeters
Versatile EMI Reduction IC 7 of 9 Notice: The information in this document is subject to change without notice. Mechanical Package Outline 8-Pin TSSOP Dimensions in inches Dimensions in millimeters Symbol Min Nor Max Min Nor Max A 0.047 1.10 A1 0.002 0.006 0.05 0.15 B 0.007 0.012 0.19 0.30 C 0.004 0.008 0.09 0.20 e 0.026 BSC 0.65 BSC Note: Controlling dimensions are millimeters
Versatile EMI Reduction IC 8 of 9 Notice: The information in this document is subject to change without notice. Ordering Codes Part Number Marking Package Type Qty per reel Temperature (°C) P2041A-08ST P2041A 8 PIN SOIC, TUBE 0 TO 70 P2041A-08SR P2041A 8 PIN SOIC, TAPE & REEL 2,500 0 TO 70 P2041A-08TT P2041A 8 PIN TSSOP, TUBE 0 TO 70 P2041A-08TR P2041A 8 PIN TSSOP, TAPE & REEL 2,500 0 TO 70 Licensed under US patent Nos 5,488,627 and 5,631,920. Preliminary datasheet. Specification subject to change without notice.
Versatile EMI Reduction IC 9 of 9 Notice: The information in this document is subject to change without notice. © 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 ch anges to this document and its products at any time without notice. Alliance assumes no responsibility for any errors t hat may appear in this document. The data contained herein represents Alliance's best data and/or estimate s at the time of issuance. Alliance rese rves 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 in tended to operate as, or provide, any guarantee or warrantee to any user or customer. Alliance does not assume any responsibility or lia bility arising out of the applic ation or use of any product described herein, and disclaims any express or implied warrant ies related to the sale and/or use of Alliance products including liability or warranties related to fitness for a particular purpose, mercha ntability, or infringement of any intellec tual 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 pa tent rights, copyrights; mask works rights, trademarks, or any other intellectual property rights of Alli ance or third parties. Alliance does not aut horize its products for use as critical components in life-supporting systems where a malfunction or fa ilure 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. 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 Part Number: P2041A Document Version: F