P2811 ALSC | Alldatasheet
Document overview
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Technical content
Features
FCC approved method of EMI attenuation Provides up to 15 dB EMI reduction Generates 1X, 2X, and 4X low EMI spread spectrum clock of the input frequency 1X: P2811, 2X: P2812, 4X: P2814 Optimized for input frequency range from 10 to 40 MHz P2811: 10 to 40 MHz P2812: 10 to 40 MHz P2814: 10 to 40 MHz Internal loop filter minimizes external components and board space Selectable spread options: Down Spread and Center Spread Low inherent cycle-to-cycle jitter Eight spread % selections: ±0.625% to –3.5% 3.3 V operating voltage CMOS/TTL compatible inputs and outputs Pinout compatible with Cypress CY25811, CY25812, and CY25814 Products available for industrial temperature range Available in 8-pin SOIC and TSSOP Product Description The P28xx is a versatile spread spectrum frequency modulator designed specifically for input clock frequencies from 10 to 40 MHz (see In put/Output Frequency Range Selections). The P28xx can generate an EMI reduced clock from crystal, ceramic resonato r, or system clock. The P28xx-A and P28xx-B offer various combinations of spread options and percentage deviations (see Output Frequency Deviation and Spread Option Selections section). These combinations include Down Spread, Center Spread and percentage deviation range from ±0.625% to -3.50%. The P28xx reduces electromagn etic interference (EMI) at the clock source, allowing a system wide EMI reduction for all the down stream clocks and data dependent signals. The P28xx allows significant system cost savings by reducing the number of circuit board layers, ferrite beads, shielding, and other pass ive components that are traditionally required to pass EMI regulations. The P28xx 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 P28xx uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all-digital method.
Applications
The P28xx is targeted towards EMI management for memory interfaces in mobile graphic chipsets and high- speed digital applications such as PC peripheral devices, consumer electronics, and embedded controller systems. Block Diagram
Low Power EMI Reduction IC 2 of 8 Notice: The information in this document is subject to change without notice. Pin Configuration Pin Description Pin# Pin Name Type Description 1 XIN I Connect to externally generated clock signal or crystal. 2 VSS P Ground Connection. C onnect to system ground. D_C I Digital logic input used to select Down (LOW) or Center (HIGH) Spread Options (see Output Frequency Deviation and Spread Option Selections). This pin has an internal pull-up resistor. SRS I Spread Range Selection. Digital logic input used to select frequency deviation (see Output Frequency Deviation and Spread Option Selections). This pin has an internal pull-up resistor.
5 ModOut O Spread Spectrum clock out put (see Input/Output Frequency Range
Selections and Output Frequency Deviation and Spread Option Selections). FRS I Frequency Range Selection. Digital logic input used to select input fre- quency range (see Input/Output Frequency Range Selections). This pin has an internal pull-up resistor. 7 VDD P Connect to +3.3 V 8 XOUT I Connect to crystal. No connect if externally generated clock signal is used. Input/Output Frequency Range Selections Part number Pin 6 P2811 (1X) P2812 (2X) P2814 (4X) FRS Input (MHz) Output (MHz) Input (MHz) Output (MHz) Input (MHz) Output (MHz) Modulation rate 0 10-20 10-20 10-20 20-40 10-20 40-80 Input frequency / 448 1 20-40 20-40 20-40 40-80 20-40 80-160 Input frequency / 896
Low Power EMI Reduction IC 3 of 8 Notice: The information in this document is subject to change without notice. Output Frequency Deviation and Spread Option Selections Part number Pin 3 D_C Pin 4 SRS Output frequency deviation and spread option 0 0 -2.50% (Down) 0 1 -3.50% (Down) 1 0 +/-1.25% (Center) P2811/12/14A 1 1 +/-1.75% (Center) 0 0 -1.25% (Down) 0 1 -1.75% (Down) 1 0 +/-0.625% (Center) P2811/12/14B 1 1 +/-0.875% (Center) 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
3.3 V, 25° C
Symbol Parameter Min Typ Max Unit VIL Input Low Voltage GND – 0.3 – 0.8 V VIH Input High Voltage – – V DD + 0.3 V IIL Input low Current (inputs D_C, SRS, and FRS) -60.00 – -20.00 µA IIH Input High Current – – 1.00 µA IXOL XOUT Output Low Current IXOH XOUT Output High Current VOL Output Low Voltage (VDD=3.3V, IOL = 20 mA) – – 0.4 V VOH Output High Voltage (VDD=3.3V, IOH = 20 mA) – – 2.8 V IDD Static Supply Current Standby Mode – 4.5 – mA ICC Dynamic Supply Current Normal Mode (3.3V and 25 pF probe loading) 7.1 fIN-min – 13.9 f IN-max mA VDD Operating Voltage – 3.3 – V tON Power Up Time (First locked clock cycle after power up) – 0.18 – mS ZOUT Clock Output Impedance – 50 – Ω
Low Power EMI Reduction IC 4 of 8 Notice: The information in this document is subject to change without notice. Symbol Parameter Min Typ Max Unit fIN Input frequency P2811/12/14 10 – 40 MHz fOUT Output frequency P2811 10 – 40 MHz Output frequency P2812 20 – 80 MHz Output frequency P2814 40 – 160 MHz tLH Output rise time (measured at 0.8V to 2.0V) 0.69 ns tHL Output fall time (measured at 2.0V to 0.8V) 0.66 ns tJC Jitter (cycle to cycle) -200 – 200 ps tD Output duty cycle 45 50 55 % 1. tLH and tHL are measured into a capacitive load of 15 pF
Low Power EMI Reduction IC 5 of 8 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 SOIC – 0.074 grams unit weight
Low Power EMI Reduction IC 6 of 8 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 TSSOP – 0.034 grams unit weight
Low Power EMI Reduction IC 7 of 8 Notice: The information in this document is subject to change without notice. Ordering Codes Part Number Marking Package Type Qty per reel Temperature P2811A-08ST P2811A 8-pin SOIC, tube 0 to 70 P2812A-08ST P2812A 8-pin SOIC, tube 0 to 70 P2814A-08ST P2814A 8-pin SOIC, tube 0 to 70 P2811A-08SR P2811A 8-pin SOIC, tape reel 2,500 0 to 70 P2812A-08SR P2812A 8-pin SOIC, tape reel 2,500 0 to 70 P2814A-08SR P2814A 8-pin SOIC, tape reel 2,500 0 to 70 P2811A-08TT P2811A 8-pin TSSOP, tube 0 to 70 P2812A-08TT P2812A 8-pin TSSOP, tube 0 to 70 P2814A-08TT P2814A 8-pin TSSOP, tube 0 to 70 P2811A-08TR P2811A 8-pin TSSOP, tape reel 2,500 0 to 70 P2812A-08TR P2812A 8-pin TSSOP, tape reel 2,500 0 to 70 P2814A-08TR P2814A 8-pin TSSOP, tape reel 2,500 0 to 70 Device Ordering Information X 28XX X- 08 XX Licensed under US patent Nos 5,488,627 and 5,631,920. Preliminary datasheet. Specification subject to change without notice. Package: ST – SOIC, TUBE SR - SOIC, T/R TT – TSSOP, TUBE TR - TSSOP, T/R F = Pb FREE DEVICE NUMBER Flow: P = Commercial Temperature Range (0°C to 70°C) I = Industrial Temperature Range (-25°C to 85°C) A = Automotive Tem perature Range (-40°C to 125°C) Pin Count
Low Power EMI Reduction IC 8 of 8 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 Preliminary Information Part Number: P2811/12/14 Document Version: