P2781 ALSC | Alldatasheet

Document overview

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Technical content

Features

ƒ Provides up to 15dB of EMI suppression ƒ FCC approved method of EMI attenuation ƒ Generates a 1X, 2X, and 4X low EMI spread spectrum clock of the input frequency ƒ Input frequency range from 3 to 78MHz ƒ External loop filter for spread % adjustment ƒ Spreading ranges from ±0.25% to ±5.0% ƒ Ultra low cycle-to-cycle jitter ƒ Zero-cycle slip ƒ 3.3V operating voltage range ƒ 10 mA output drives ƒ TTL or CMOS compatible outputs ƒ Ultra-low power CMOS design ƒ P278XA is available in 8 pin SOIC and TSSOP Packages ƒ Available for industrial and automotive temperature ranges. Product Description The P278xA is a versatile spread spectrum frequency modulator designed specifically for digital camera and other digital video and imaging applications. The P278xA reduces electromagnetic inte rference (EMI) at the clock source, which provides system wide reduction of EMI of all clock dependent signals. The P278xA allows significant system cost savings by reducing the number of circuit board layers and shielding that are traditionally required to pass EMI regulations. The P278xA uses the most efficient and optimized modulation profile approved by the FCC. The P278xA 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 si gnificantly 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 P278xA is targeted towa rds MFP, xDSL, fax modem, set-top box, USB controller, DSC, and embedded systems. Block Diagram Crystal Oscillator Frequency Divider Feedback Divider Phase Detector Modulation Output Divider VCO XIN /CLKIN XOUT FS0 FS1 LF VDD VSS PLL ModOUT

rev 1.5 General Purpose EMI Reduction IC 2 of 11 Notice: The information in this document is subject to change without notice. Pin Configuration Pin Description (P278XA) Pin# Pin Name Type Description 1 XIN/CLKIN I Connect to crystal or clock input. This pin has dual functions. It can be connected either to 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 FS1 I

Digital logic input used to select input frequency range (see the Input Frequency Selection Table). This pin has an internal pull-up resistor.

4 LF I

External Loop Filter for the PLL. By changing the value of the CRC circuit, the percentage spread can be adjusted accord ingly. See the Loop Filter Selection Table for detail value. 5 VSS I Ground Connection. Connect to system ground. 6 ModOUT O Spread Spectrum Clock Output.

7 FS0 I

Digital logic input used to select input frequency range (see the Input Frequency Selection Table). This pin has an internal pull-up resistor. 8 VDD P Connect to +3.3 V Input Frequency Selection Table Output Frequency Scaling (MHz) FS1 FS0 Input (MHz) P2781A P2782A P2784A Modulation Rate (KHz) 0 0 3 to 9 3 to 9 6 to 18 12 to 36 Fin / 128 0 1 10 to 19 10 to 19 20 to 38 40 to 76 Fin / 256 1 0 20 to 38 20 to 38 40 to 76 80 to 152 Fin / 512 1 1 39 to 78 39 to 78 78 to 156 156 to 312 Fin / 1024 XIN / CLKIN XOUT FS1 LF VDD FS0 ModOUT VSS P278XA-08S P278XA-08T Standard pin Configuration offered in both 8 pin SOIC and TSSOP Packages

rev 1.5 General Purpose EMI Reduction IC 3 of 11 Notice: The information in this document is subject to change without notice. Loop Filter Selection Table VDD 3.3V Contact Alliance for loop values that are not listed in the table and for component selection values for industrial and automotive temperatures. BW = ±0.50% BW = ±0.75% BW = ±1.00% BW = ±1.25% Input MHz FS1 FS0 C1 (pF) (pF) (ohm) (pF) (pF) (ohm) (pF) (pF) (ohm) (pF) (pF) (ohm) 3 0 0 270 330,000 220 270 330,000 300 270 100,000 390 560 100,000 510 4 0 0 270 100,000 270 270 100,000 390 270 100,000 560 560 100,000 680 5 0 0 270 100,000 390 270 100,000 560 270 100,000 750 560 100,000 910 6 0 0 270 100,000 510 270 100,000 750 270 10,000 1,000 680 6,800 1,200 7 0 0 270 100,000 620 270 100,000 1,000 270 5,600 1,200 330 3,300 1,200 8 0 0 270 100,000 820 270 100,000 1,200 270 12,000 2,200 680 6,800 2,200 9 0 0 270 100,000 1,000 270 100,000 1,500 270 5,600 2,200 270 2,700 2,200 10 0 1 270 100,000 330 270 100,000 510 270 100,000 750 560 100,000 910 11 0 1 270 100,000 390 270 100,000 560 270 100,000 866(1%) 560 100,000 1,100 12 0 1 270 100,000 510 270 100,000 750 270 10,000 1,000 680 6,800 1,200 13 0 1 270 100,000 560 270 100,000 820 270 12,000 1,200 470 4,700 1,200 14 0 1 270 100,000 620 270 100,000 1,000 270 5,600 1,200 330 3,300 1,200 15 0 1 270 100,000 750 270 100,000 1,100 270 3,900 1,200 330 3,300 1,500 16 0 1 270 100,000 820 270 100,000 1,200 270 12,000 2,200 680 6,800 2,200 17 0 1 270 100,000 910 270 100,000 1,300 270 10,000 2,200 390 3,900 2,200 18 0 1 270 100,000 1,000 270 100,000 1,500 270 5,600 2,200 270 2,700 2,200 19 0 1 270 100,000 1,200 270 100,000 1,600 270 3,300 2,200 270 2,700 2,700 20 0 0 270 100,000 330 270 100,000 560 270 100,000 750 560 100,000 910 21-22 1 0 270 100,000 390 270 100,000 620 270 100,000 866 (1%) 560 100,000 1,100 23-24 1 0 270 100,000 510 270 100,000 750 270 10,000 1,000 680 6,800 1,200 25-26 1 0 270 100,000 560 270 100,000 820 270 12,000 1,200 470 4,700 1,200 27-28 1 0 270 100,000 620 270 100,000 1,000 270 6,800 1,200 330 3,300 1,200 29-30 1 0 270 100,000 750 270 100,000 1,100 270 3,900 1,200 330 3,300 1,500 31-32 1 0 270 100,000 820 270 100,000 1,200 270 12,000 2,200 680 6,800 2,200 33-34 1 0 270 100,000 910 270 100,000 1,300 270 10,000 2,200 390 3,900 2,200 35-36 1 0 270 100,000 1,000 270 100,000 1,500 270 5,600 2,200 270 2,700 2,200 37-38 1 0 270 100,000 1,200 270 100,000 1,600 270 3,300 2,200 270 2,700 2,700 39-42 1 1 270 100,000 330 270 100,000 560 270 100,000 750 560 100,000 910 43-46 1 1 270 100,000 390 270 100,000 620 270 100,000 866 (1%) 560 100,000 1,100 47-50 1 1 270 100,000 510 270 100,000 750 270 10,000 1,000 680 6,800 1,200 51-54 1 1 270 100,000 560 270 100,000 820 270 12,000 1,200 470 4,700 1,200 55-58 1 1 270 100,000 620 270 100,000 1,000 270 6,800 1,200 330 3,300 1,200 59-62 1 1 270 100,000 750 270 100,000 1,100 270 3,900 1,200 330 3,300 1,500 63-66 1 1 270 100,000 820 270 100,000 1,200 270 12,000 2,200 680 6,800 2,200 67-70 1 1 270 100,000 910 270 100,000 1,300 270 8,200 2,200 390 3,900 2,200 71-74 1 1 270 100,000 1,000 270 100,000 1,600 270 5,600 2,200 270 2,700 2,200 75-78 1 1 270 100,000 1,200 270 100,000 1,800 270 3,300 2,200 270 2,700 2,700

1 The BW value is representative of typical conditions

rev 1.5 General Purpose EMI Reduction IC 4 of 11 Notice: The information in this document is subject to change without notice. Spread Spectrum Selection The P278xA performs Zero Cycle Slip when set at low percentag e spreading. This allows no occurrence of system timing error. The optimal setting should minimize system EMI to the fullest without affect ing 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.) The P2781A is designed for PC peripheral, networking, noteb ook PC, and LCD monitor applications. It is optimized for operation between 3 to 78MHz range. In the following applic ation schematic example, t he P2781A spread percentage selection is determined by the external LF value specified in the Loop Filter Selection Tabl e. The Input Frequency Selection Table specifies the input frequency range. The external LF allows the user to fine tune the spread percentage to optimize the EMI reduction benefits of the spread spectrum. Note: Both logic input pins FS1 and FS0 have to be connected to either VDD or VSS. Do not leave them floating. VDD FS0 ModOUT VSSLF FS1 XOUT XIN/CLKIN P2781A +3.3V Modulated 16MHz Clock To target Chip

16 MHz

0.1µF C2 C1

0 Ohm

2.2 K

rev 1.5 General Purpose EMI Reduction IC 5 of 11 Notice: The information in this document is subject to change without notice. Absolute Maximum Ratings Symbol Parameter Rating Unit VDD Supply voltage, DC (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 (V I<0 or VI>VDD) -50 to +50 mA IOK Output clamp current (V I<0 or VI>VDD) -50 to +50 mA TS Storage temperature -65 to +125 °C TA Ambient temperature range, under bias -55 to 125 °C TJ Junction temperature 150 °C Lead temperature (soldering 10 sec) 260 °C Input static discharge voltage protection (As per JEDEC STD22- A114-B) 2 kV Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. (Test condition: All parameters are measured at room temperature (+25°C) unless otherwise stated) Symbol Parameter Min Typ Max Unit VIL Input low voltage VSS – 0.3 - 0.8 V VIH Input high voltage 2.0 - VDD +0.3 V IIL Input low current (internal input pull-up resistor on FS0 and FS1) - 60 - µA IIH Input high current (internal input pull-up resistor on FS0 and FS1) - 60 - µA IXOL XOUT output low current - 10 - mA IXOH XOUT output high current - 10 - mA VOL Output low voltage (VDD = 3.3V, I OL = 20mA) - - 0.4 V VOH Output high voltage (VDD = 3.3V, I OH = 20mA) 2.5 - - V IDD Static supply current - 3 - mA ICC Typical dynamic supply current (25pF scope probe loading) 5.2 at 3MHz - 21.2 at 82MHz mA VDD Operating volt age 3.0 3.3 3.6 V

rev 1.5 General Purpose EMI Reduction IC 6 of 11 Notice: The information in this document is subject to change without notice. Symbol Parameter Min Typ Max Unit fIN Input frequency: P278XA 3 - 78 MHz fOUT Output frequency: P2781A P2782A P2784A 156 312 MHz tLH P278XA Output rise time (measured at 0.8 V to 2.0 V, 25pF scope probe loading) - 1 - nS tHL P278XA Output fall time (measured at 2.0 V to 0.8 V, 25 pF scope probe loading) - 1 - nS tJC P2781A Jitter (cycle to cycle, ± 6sigma, 1000 sweeps, ± 0.5% spread, I/O frequency = 16MHz) - ±250 - pS tD P2781A Output duty cycle deviation (error from 50% duty cycle, 25pF scope probe loading) ±1 at 3MHz - ±2 at 82MHz % P278XA Frequency deviation tolerance from BW% stated in the Loop Filter Selection Table -20 0 +20 %

rev 1.5 General Purpose EMI Reduction IC 7 of 11 Notice: The information in this document is subject to change without notice.

Package Information

Mechanical Package Outline 8-Pin SOIC Package D E H D A2 A θ L C B e Dimensions Inches Millimeters Symbol 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 θ 0° 8° 0° 8° Note: Controlling dimensions are millimeters SOIC - 0.074 grams unit weight

rev 1.5 General Purpose EMI Reduction IC 8 of 11 Notice: The information in this document is subject to change without notice. E H A D B C L θ e Mechanical Package Outline 8-Pin TSSOP Package Dimensions Inches Millimeters Symbol Min Max Min Max A 0.043 1.10 A1 0.002 0.006 0.05 0.15 A2 0.033 0.037 0.85 0.95 B 0.008 0.012 0.19 0.30 c 0.004 0.008 0.09 0.20 D 0.114 0.122 2.90 3.10 E 0.169 0.177 4.30 4.50 e 0.026 BSC 0.65 BSC H 0.252 BSC 6.40 BSC L 0.020 0.028 0.50 0.70 θ 0° 8° 0° 8° Note: Controlling dimensions are millimeters TSSOP - 0.0325 grams unit weight

rev 1.5 General Purpose EMI Reduction IC 9 of 11 Notice: The information in this document is subject to change without notice. Ordering Codes Ordering # Marking Package Type QTY / Reel Temperature P278XA-08ST P278XA 8 PIN SOIC, TUBE See flow P278XA-08SR P278XA 8 PIN SOIC, TAPE & REEL 2,500 See flow P278XA-08TT P278XA 8 PIN TSSOP, TUBE See flow P278XA-08TR P278XA 8 PIN TSSOP, TAPE & REEL 2,500 See flow P278XAF-08ST P278XAF 8 PIN SOIC, TUBE, Pb Free See flow P278XAF-08SR P278XAF 8 PIN SOIC, TAPE AND REEL,Pb Free 2,500 See flow P278XAF-08TT P278XAF 8 PIN TSSOP, TUBE, Pb Free See flow P278XAF-08TR P278XAF 8 PIN TSSOP, T APE AND REEL, Pb Free 2,500 See flow P278XAG-08ST P278XAG 8 PIN SOIC, TUBE, Green See flow P278XAG-08SR P278XAG 8 PIN SOIC, TAPE AND REEL, Green 2,500 See flow P278XAG-08TT P278XAG 8 PIN TSSOP, TUBE, Green See flow P278XAG-08TR P278XAG 8 PIN TSSOP, TAPE AND REEL, Green 2,500 See flow I278XA-08ST I278XA 8 PIN SOIC, TUBE See flow I278XA-08SR I278XA 8 PIN SOIC, TAPE & REEL 2,500 See flow I278XA-08TT I278XA 8 PIN TSSOP, TUBE See flow I278XA-08TR I278XA 8 PIN TSSOP, TAPE & REEL 2,500 See flow I278XAF-08ST I278XAF 8 PIN SOIC, TUBE, Pb Free See flow I278XAF-08SR I278XAF 8 PIN SOIC, TAPE AND REEL,Pb Free 2,500 See flow I278XAF-08TT I278XAF 8 PIN TSSO P, TUBE, Pb Free See flow I278XAF-08TR I278XAF 8 PI N TSSOP, TAPE AND REEL, Pb Free 2,500 See flow I278XAG-08ST I278XAG 8 PIN SOIC, TUBE, Green See flow I278XAG-08SR I278XAG 8 PIN SOIC, TAPE AND REEL, Green 2,500 See flow I278XAG-08TT I278XAG 8 PIN T SSOP, TUBE, Green See flow I278XAG-08TR I278XAG 8 PI N TSSOP, TAPE AND REEL, Green 2,500 See flow X278XA-08ST X278XA 8 PIN SOIC, TUBE See flow X278XA-08SR X278XA 8 PIN SOIC, TAPE & REEL 2,500 See flow X278XA-08TT X278XA 8 PIN TSSOP, TUBE See flow X278XA-08TR X278XA 8 PIN TSSOP, TAPE & REEL 2,500 See flow X278XAF-08ST X278XAF 8 PIN SOIC, TUBE, Pb Free See flow X278XAF-08SR X278XAF 8 PIN SOIC, TAPE AND REEL, Pb Free 2,500 See flow X278XAF-08TT X278XAF 8 PIN TSSOP, TUBE, Pb Free See flow X278XAF-08TR X278XAF 8 PIN TSSOP, T APE AND REEL, Pb Free 2,500 See flow X278XAG-08ST X278XAG 8 PIN SOIC, TUBE, Green See flow X278XAG-08SR X278XAG 8 PIN SOIC, TAPE AND REEL, Green 2,500 See flow X278XAG-08TT X278XAG 8 PIN TSSOP, TUBE, Green See flow X278XAG-08TR X278XAG 8 PIN TSSOP, TAPE AND REEL, Green 2,500 See flow

rev 1.5 General Purpose EMI Reduction IC 10 of 11 Notice: The information in this document is subject to change without notice. Device Ordering Information P278XA F- 08 XX Licensed under US patent #5,488,627, #6,646,463 and #5,631,920 Package: ST – SOIC, TUBE SR - SOIC, T/R TT – TSSOP, TUBE TR - TSSOP, T/R DEVICE NUMBER Flow: P = Commercial Temperature Range (0°C to 70°C) I = Industrial Temperature Range (-40°C to 85°C) X = Automotive Tem perature Range (-40°C to 125°C) Pin Count F = LEAD FREE or RoHS COMPLIANT PART G = GREEN

rev 1.5 General Purpose EMI Reduction IC 11 of 11 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 2575, 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: P2781/82/84 Document Version: 1.5 Note: This product utilizes US Patent # 6,646,463 Impedance Emulator Patent issued to Alliance Semiconductor, dated 11-11-2003