P2560B ALSC | Alldatasheet
Document overview
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Technical content
Features
FCC approved method of EMI attenuation Generates a low EMI spread spectrum and a non- spread reference signal of the input clock frequency Optimized for input frequency range from 20 to 32 MHz Internal loop filter minimizes external components and board space Two selectable spread ranges 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 SSON pin for Spread Spectrum On/Off and Standby Mode controls Available in 8-pin SOIC and TSSOP Product Description The P2560B is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. It reduces el ectromagnetic interference (EMI) at the clock source allowing system-wide reduction of EMI of downstream clock and data 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 P2560B modulates the output of a single PLL in order to spread the bandwi dth 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 P2560B uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all-digital method.
Applications
The P2560B is targeted toward the notebook VGA chip and other displays using an LVDS interface, PC peripheral devices, and embedded systems Block Diagram
rev 1.0 Low Frequency EMI Reduction 2 of 7 Notice: The information in this document is subject to change without notice. Pin Configuration Standby Mode Selection CLKIN SSON/SBM Spread Spectrum ModOUT PLL Mode Disabled 0 N/A Disabled Disabled Standby Disabled 1 N/A Disabled Free running Free running Enabled 0 Off Reference Disabled Buffer out Enabled 1 On Normal Normal Normal Spread Range Selection, VDD = 3.3 V CLKIN frequency Spreading range Modulation rate 20 MHz ±1.16% 25 MHz ±1.13% 27 MHz ±1.11% 30 MHz ±1.0% 32 MHz ±1.0% (CLKIN/10) * 20.83 kHz Pin Description Pin# Pin Name Type Description
1 XIN/CLK I
Crystal connection or external reference frequency input. This pin has dual functions. It can be connected to either an external crystal or an external reference clock. 2 XOUT O Crystal connection. If using an external reference, this pin must be left unconnected.
3 DIV2 I
Digital logic input used to select normal output mode or divide-by-2 output mode. When this pin is HIGH, the frequency of the output clock is the same as the input clock frequency. When it is tied LOW, the output frequency is half the input clock frequency. This pin has an internal pull-up resistor. 4 VSS P Ground to entire chip.
5 SR0 I Digital logic input used to select Spreading Range (Refer Spread Deviation
Table). This pin has an internal pull-up resistor.
6 SSON# I
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. 7 MODOUT O Spread spectrum low EMI output. 8 VDD P Power supply for the entire chip (5V). P2560B
rev 1.0 Low Frequency EMI Reduction 3 of 7 Notice: The information in this document is subject to change without notice. Schematic for Notebook VGA Application P2560B
rev 1.0 Low Frequency EMI Reduction 4 of 7 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 and SSON/SBM) – – -35 µA IIH Input high current – – 35 µA at 0.4 V, VDD = 3.3V – 3 – mA IXOL XOUT output low current at 0.4 V, VDD = 5.0 V – 20 – mA at 2.5 V, VDD = 3.3 V – 3 – mA IXOH XOUT output high current at 4.5 V, VDD = 5.0 V – 20 – mA VDD = 3.3 V, IOL = 20 mA – – 0.4 V VOL Output low voltage VDD = 5.0 V, IOL = 20 mA – – – V VDD = 3.3 V, IOL = 20 mA 2.5 – – V VOH Output high voltage VDD = 5.0 V, IOL = 20 mA 4.5 – – V IDD Static supply current standby mode – 0.6 – mA Normal mode: fIN-min fIN-typ fIN-max 3.3 V and 10 pF loading 3.2 – 7.0 mA ICC Dynamic supply current 5.0 V and 10 pF loading 6.2 – 13.6 mA VDD Operating voltage 2.7 3.3 5.5 V tON Power-up time (first locked cycle after power up) – 0.18 – mS ZOUT Clock output impedance – 50 – Ω Symbol Parameter Min Typ Max Unit fIN Input frequency 20 – 32 MHz fOUT Output frequency 20 – 32 MHz tLH 1 Output rise time Measured at 1.2 V to 3.75 V – 0.75 – ns tHL 1 Output fall time Measured at 1.2 V to 3.75 V – 0.75 – ns tJC Jitter (cycle to cycle) – – 360 ps tD Output duty cycle 45 50 55 %
rev 1.0 Low Frequency EMI Reduction 5 of 7 Notice: The information in this document is subject to change without notice.
Package Information
e 0.050 BSC 1.27 BSC Note: Controlling dimensions are millimeters. SOIC - 0.074 grams unit weight 8-Pin TSSOP INCHES MILLIMETERS SYMBOL MIN NOR MAX MIN NOR MAX 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 a 0° – 8° 0° – 8° Note: Controlling dimensions are millimeters. TSSOP - 0.034 grams unit weight P2560B
rev 1.0 Low Frequency EMI Reduction 6 of 7 Notice: The information in this document is subject to change without notice.
Ordering Information
Ordering Code Package Type Operating Range P2560B-08ST 8-pin 150mil SOIC Commercial I2560B-08SR 8-pin SOIC T&R Industrial P2560BF-08ST 8-pin TSSOP Tube Commercial I2560BF-08SR 8-pin TSSOP T&R Industrial Package: ST: SOIC in TUBE SR: SOIC in TAPE & REEL TT: TSSOP in TUBE TR: TSSOP in TAPE & REEL PIN COUNT F = Pb FREE PART NUMBER Flow: P: Commercial temperature Range (0°C to 70°C) I: Industrial Temperature Range (-20°C to 85°C) X2 5 6 0 B X - 0 8XX
rev 1.0 Low Frequency EMI Reduction 7 of 7 Notice: The information in this document is subject to change without notice. Licensed under US patent number 5,488,627 and 5,631,920. © 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: P2560B Document Version: v1.0