P2781/82/84 General Purpose EMI Reduction IC Features • Provides up to 15dB of EMI suppression • FCC approved method of EMI attenuation • Generates a 1X, 2X, and 4X low EMI spread spectrum clock of the input frequency • Input frequency range from 3 to 78MHz 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 result 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. • External loop filter for spread % adjustment • Spreading ranges from ±0.25% to ±5.0% • Ultra low cycle-to-cycle jitter • Zero-cycle slip • 3.3V operating voltage range • Ultra-low power CMOS design • P278xA is available in an 8 pin SOIC Package 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 interference (EMI) at the clock Applications The P278xA is targeted towards MFP, xDSL, fax modem, set-top box, USB controller, DSC, and embedded systems. Block Diagram FS0 FS1 LF VDD PLL Modulation XIN / CLKIN XOUT Crystal Oscillator Frequency Divider Feedback Divider Phase Detector Output Divider VCO ModOUT VSS ©2010 SCILLC. All rights reserved. NOVEMBER 2010 – Rev. 2.1 Publication Order Number: P2781/82/84 P2781/82/84 Pin Configuration XIN / CLKIN 1 XOUT 2 FS1 3 LF 4 8 VDD 7 FS0 P278xA 6 ModOUT 5 VSS Standard pin Configuration offered in both 8 pin SOIC Packages. Pin Description (P278xA) Pin# Pin Name Type Description 1 XIN/CLKIN I 2 XOUT O 3 FS1 I 4 LF I 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 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. Crystal connection. If using an external reference, this pin must be left unconnected. Digital logic input used to select input frequency range (see the Input Frequency Selection Table). This pin has an internal pull-up resistor. External Loop Filter for the PLL. By changing the value of the CRC circuit, the percentage spread can be adjusted accordingly. See the Loop Filter Selection Table for detail value. Input Frequency Selection Table FS1 FS0 Input (MHz) 0 0 0 Output Frequency Scaling (MHz) Modulation Rate (KHz) P2781A P2782A P2784A 3 to 9 3 to 9 6 to 18 12 to 36 Fin / 128 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 Rev. 2 | Page 2 of 8 | www.onsemi.com P2781/82/84 Loop Filter Selection Table VDD 3.3V Contact ON Semiconductor for loop values that are not listed in the table and for Component selection values for industrial and automotive temperatures. Input MHz 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21-22 23-24 25-26 27-28 29-30 31-32 33-34 35-36 37-38 39-42 43-46 47-50 51-54 55-58 59-62 63-66 67-70 71-74 75-78 BW = ±0.50%1 FS1 FS0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 BW = ±0.75%1 BW = ±1.00%1 C1 (pF) C2 (pF) R1 (ohm) C1 (pF) C2 (pF) R1 (ohm) C1 (pF) 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 330,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 220 270 390 510 620 820 1,000 330 390 510 560 620 750 820 910 1,000 1,200 330 390 510 560 620 750 820 910 1,000 1,200 330 390 510 560 620 750 820 910 1,000 1,200 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 330,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 100,000 300 390 560 750 1,000 1,200 1,500 510 560 750 820 1,000 1,100 1,200 1,300 1,500 1,600 560 620 750 820 1,000 1,100 1,200 1,300 1,500 1,600 560 620 750 820 1,000 1,100 1,200 1,300 1,600 1,800 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 270 Note: 1. The BW value is representative of typical conditions. Rev. 2 | Page 3 of 8 | www.onsemi.com C2 (pF) R1 (ohm) 100,000 390 100,000 560 100,000 750 10,000 1,000 5,600 1,200 12,000 2,200 5,600 2,200 100,000 750 100,000 866(1%) 10,000 1,000 12,000 1,200 5,600 1,200 3,900 1,200 12,000 2,200 10,000 2,200 5,600 2,200 3,300 2,200 100,000 750 100,000 866 (1%) 10,000 1,000 12,000 1,200 6,800 1,200 3,900 1,200 12,000 2,200 10,000 2,200 5,600 2,200 3,300 2,200 100,000 750 100,000 866 (1%) 10,000 1,000 12,000 1,200 6,800 1,200 3,900 1,200 12,000 2,200 8,200 2,200 5,600 2,200 3,300 2,200 BW = ±1.25%1 C1 (pF) C2 (pF) R1 (ohm) 560 560 560 680 330 680 270 560 560 680 470 330 330 680 390 270 270 560 560 680 470 330 330 680 390 270 270 560 560 680 470 330 330 680 390 270 270 100,000 100,000 100,000 6,800 3,300 6,800 2,700 100,000 100,000 6,800 4,700 3,300 3,300 6,800 3,900 2,700 2,700 100,000 100,000 6,800 4,700 3,300 3,300 6,800 3,900 2,700 2,700 100,000 100,000 6,800 4,700 3,300 3,300 6,800 3,900 2,700 2,700 510 680 910 1,200 1,200 2,200 2,200 910 1,100 1,200 1,200 1,200 1,500 2,200 2,200 2,200 2,700 910 1,100 1,200 1,200 1,200 1,500 2,200 2,200 2,200 2,700 910 1,100 1,200 1,200 1,200 1,500 2,200 2,200 2,200 2,700 P2781/82/84 Spread Spectrum Selection The P278xA performs Zero Cycle Slip when set at low percentage spreading. This allows no occurrence of system timing error. 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.) The P2781A is designed for PC peripheral, networking, notebook PC, and LCD monitor applications. It is optimized for operation between 3 to 78MHz range. In the following application schematic example, the P2781A spread percentage selection is determined by the external LF value specified in the Loop Filter Selection Table. 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. +3.3V 16 MHz 1 XIN/CLKIN VDD 8 2 XOUT 3 FS1 C2 R1 C1 4 LF 0 Ohm FS0 7 ModOUT 6 VSS 5 P278xA 2.2 K 0.1µF Modulated 16MHz Clock To target Chip Note: Both logic input pins FS1 and FS0 have to be connected to either VDD or VSS. Do not leave them floating. Rev. 2 | Page 4 of 8 | www.onsemi.com P2781/82/84 Absolute Maximum Ratings Symbol VDD, VIN TSTG Rating Unit Voltage on any pin with respect to Ground Parameter -0.5 to +4.6 V Storage temperature -65 to +125 °C Ts Max. Soldering Temperature (10 sec) 260 °C TJ Junction Temperature 150 °C TDV Static Discharge Voltage (As per JEDEC STD22- A114-B) 2 KV Note: These are stress ratings only and are not implied for functional use. Exposure to absolute maximum ratings for prolonged periods of time may affect device reliability. Operating Conditions Parameter VDD Description Min Max Unit Supply Voltage 3.0 3.6 V -40 TA Operating Temperature (Ambient Temperature) +85 °C CL Load Capacitance 15 pF CIN Input Capacitance 7 pF DC Electrical Characteristics (Test condition: All parameters are measured at room temperature (+25°C) unless otherwise stated.) Symbol Parameter VIL Input low voltage VIH IXOL Input high voltage Input low current (internal input pull-up resistor on FS0 and FS1) Input high current (internal input pull-up resistor on FS0 and FS1) XOUT output low current IXOH XOUT output high current VOL Output low voltage (VDD = 3.3V, IOL = 20mA) VOH Output high voltage (VDD = 3.3V, IOH = 20mA) IDD Static supply current Typical dynamic supply current (25pF scope probe loading) Operating voltage IIL IIH ICC VDD Rev. 2 | Page 5 of 8 | www.onsemi.com Max Unit VSS – 0.3 Min Typ 0.8 V 2.0 VDD +0.3 V 60 µA 60 µA 10 mA 10 mA 0.4 2.5 V 3 5.2 at 3MHz 3.0 V 3.3 mA 21.2 at 82MHz mA 3.6 V P2781/82/84 AC Electrical Characteristics Symbol fIN fOUT Parameter Input frequency: P278xA Output frequency: Min Typ Max 3 78 P2781A 3 78 P2782A 6 156 P2784A 12 312 Unit MHz tLH P278xA Output rise time (measured at 0.8V to 2.0V, 25pF scope probe loading) 1 nS tHL P278xA Output fall time (measured at 2.0V to 0.8V, 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) ∆F P278xA Frequency deviation tolerance from BW% stated in the Loop Filter Selection Table Rev. 2 | Page 6 of 8 | www.onsemi.com ±1 @ 3MHz -20 0 ±2 @ 82MHz % +20 % P2781/82/84 Package Information 8-Pin SOIC Package H E D A2 A θ C D e A1 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 θ 0° 8° Note: Controlling dimensions are millimeters. SOIC - 0.074 grams unit weight. Rev. 2 | Page 7 of 8 | www.onsemi.com 0.41 1.27 0° 8° P2781/82/84 Ordering Codes Ordering # Top Marking Package Type Temperature P2781AF-08ST ABG 8 PIN SOIC, TUBE, Pb Free 0°C to + 70°C P2781AF-08SR ABG 8 PIN SOIC, TAPE AND REEL,Pb Free 0°C to +70°C I2781AF-08ST ABH 8 PIN SOIC, TUBE, Pb Free I2781AG-08SR ABJ 8 PIN SOIC, TAPE AND REEL, Green -40°C to +85°C -40°C to +85°C P2782AF-08SR ABK 8 PIN SOIC, TAPE AND REEL,Pb Free 0°C to +70°C P2784AF-08SR ABO 8 PIN SOIC, TAPE AND REEL,Pb Free 0°C to +70°C A “microdot” placed at the end of last row of marking or just below the last row toward the center of package indicates Pb-free. are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes ON Semiconductor and without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer's technical experts. SCILLC does not convey any license under its patent rights nor the rights of others. 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