P2779A Product Preview Low-Cost Notebook EMI Reduction IC Product Description The P2779A is a versatile spread spectrum frequency modulator designed specifically for mobile and digital camera and other digital video and imaging applications. The P2779A reduces electromagnetic interference (EMI) at the clock source, which provides system−wide reduction of EMI of all clock dependent signals. The P2779A allows significant system cost savings by reducing the number of circuit board layers and shielding that are traditionally required to pass EMI regulations. The P2779A uses the most efficient and optimized modulation profile approved by the FCC. The P2779A 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. The P2779A is targeted toward mobile 3D graphics chip set applications. Features • Provides up to 15 dB of EMI Suppression • FCC Approved Method of EMI Attenuation • Generates a 1X Low EMI Spread Spectrum Clock of the Input • SOIC−8 S SUFFIX CASE 751BD TSSOP−8 T SUFFIX CASE 948AL PIN CONFIGURATION XIN / CLKIN XOUT PD 1 VDD P2779A REF ModOUT VSS LF (Top View) Applications • • • • • • • • • http://onsemi.com ORDERING INFORMATION See detailed ordering and shipping information in the package dimensions section on page 7 of this data sheet. Frequency Operates between 20 MHz and 38 MHz Input Frequency Range External Loop Filter for Spread Percentage Adjustment Spreading Ranges from ±0.25% to ±2.5% Ultra Low Cycle−to−Cycle Jitter Zero−Cycle Slip at Small Deviations 3.3 V Operating Voltage Low Power CMOS Design Available in 8−pin SOIC and TSSOP Packages Available in Industrial Temperature Operating Range (−40°C to +85°C) These are Pb−Free Devices This document contains information on a product under development. ON Semiconductor reserves the right to change or discontinue this product without notice. © Semiconductor Components Industries, LLC, 2011 August, 2011 − Rev. P2 1 Publication Order Number: P2779A/D P2779A PD VDD LF PLL Modulation XIN Frequency Divider Crystal Oscillator XOUT Phase Detector Feedback Divider Loop Filter Output Divider VCO ModOUT REF Figure 1. Block Diagram VSS Table 1. ABSOLUTE MAXIMUM RATINGS Symbol VDD, VIN TSTG Parameter Rating Unit Voltage on any pin with respect to Ground −0.5 to +4.6 V Storage temperature −65 to +125 °C TA Operating temperature −40 to +85 °C Ts Max. Soldering Temperature (10 sec) 260 °C TJ Junction Temperature 150 °C 2 KV TDV Static Discharge Voltage (As per JEDEC STD22− A114−B) Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Table 2. PIN DESCRIPTION Pin# Pin Name Type 1 XIN / CLKIN I Connect to crystal or clock input. Description 2 XOUT O Crystal output. 3 PD I Power−down control pin. Pull low to enable power−down mode. This pin has an internal pull−up resistor. (Note 1) 4 LF I External loop filter for the PLL. By changing the value of the CRC circuit, the percentage spread can be adjusted accordingly. (See Loop Filter Selection Table for detail values.) 5 VSS P Ground connection. Connect to system ground. 6 ModOUT O Spread spectrum clock output. 7 REF O Provides a reference clock output of the input frequency. 8 VDD P Connect to +3.3 V. 1. Connect to VDD if not used. http://onsemi.com 2 P2779A Loop Filter Selection Table VDD 3.3 V Pin 4 LF R1 C2 C1 Table 3. LOOP FILTER SELECTION TABLE VDD 3.3 V (Note 2) BW = +0.50% BW = +0.75% BW = +1.00% Input (MHz) FS1 FS0 C1 (pF) C2 (pF) R1 (W) C1 (pF) C2 (pF) R1 (W) C1 (pF) C2 (pF) BW = +1.25% R1 (W) C1 (pF) C2 (pF) R1 (W) 20 1 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 2. Please contact factory for loop filter values if desired spread settings are not listed. Spread Spectrum Selection The P2779A is designed for PC peripheral, networking, notebook PC, and LCD monitor applications. It is optimized for operation from 20 MHz to 38 MHz. The P2779A’s spread percentage selection is determined by the external LF value specified in the Loop Filter Selection Table. The external LF allows the user to fine tune the spread percentage to optimize the EMI reduction benefits of the spread spectrum. The P2779A performs zero cycle slip when set at low percentage spreading. This prevents any 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 that the center frequency is the frequency of the external reference input on XIN / CLKIN, pin 1.) VDD 1 XIN / CLKIN 8 27 MHz VDD C2 R1 2 XOUT REF 7 3 PD ModOUT 6 4 LF VSS 5 P2779A 0.1 mF C1 Figure 2. Application Schematic http://onsemi.com 3 +3.3 V Modulated 27 MHz PD selection: Power dissipation can be reduced by completely turning off the IC. P2779A Table 4. DC ELECTRICAL CHARACTERISTICS 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 − 60 − mA IIH Input high current − 0 − mA IXOL XOUT output low current (at 0.4 V, VDD = 3.3 V) − 10 − mA IXOH XOUT output high current (at 2.5 V, VDD = 3.3 V) − 10 − mA VOL Output low voltage (VDD = 3.3 V, IOL = 20 mA) − − 0.4 V VOH Output high voltage (VDD = 3.3 V, IOH = 20 mA) 2.5 − − V IDD Static supply current − 3 − mA ICC Dynamic supply current (3.3 V, 25 pF loading, 32 MHz) VDD Operating voltage − 12 − mA 3.0 3.3 3.6 V tON Power−up time (first locked cycle after power up) − 7 − mS Clock output impedance − 28 − W Min Typ Max Unit Input frequency 20 − 38 MHz Output frequency 20 − 38 MHz tLH (Note 3) Output rise time (measured at 0.8 V to 2.0 V) − 1 − nS tHL (Note 3) Output fall time (measured at 2.0 V to 0.8 V) − 1 − nS tJC Jitter (Cycle−to−cycle) − ±175 − pS tD Output duty cycle 45 50 55 % ZOUT Table 5. AC ELECTRICAL CHARACTERISTICS Symbol fIN fOUT Parameter 3. tLH and tHL are measured into a capacitive load of 15 pF. Static Discharge Voltage (As per JEDEC STD22− A114−B) http://onsemi.com 4 P2779A PACKAGE DIMENSIONS TSSOP8, 4.4x3 CASE 948AL−01 ISSUE O b SYMBOL MIN NOM A E1 E MAX 1.20 A1 0.05 A2 0.80 b 0.19 0.30 c 0.09 0.20 D 2.90 3.00 3.10 E 6.30 6.40 6.50 E1 4.30 4.40 4.50 0.15 0.90 e 0.65 BSC L 1.00 REF L1 0.50 θ 0º 0.60 1.05 0.75 8º e TOP VIEW D A2 c q1 A A1 L1 SIDE VIEW L END VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MO-153. http://onsemi.com 5 P2779A PACKAGE DIMENSIONS SOIC 8, 150 mils CASE 751BD−01 ISSUE O E1 E SYMBOL MIN A 1.35 1.75 A1 0.10 0.25 b 0.33 0.51 c 0.19 0.25 D 4.80 5.00 E 5.80 6.20 E1 3.80 4.00 MAX 1.27 BSC e PIN # 1 IDENTIFICATION NOM h 0.25 0.50 L 0.40 1.27 θ 0º 8º TOP VIEW D h A1 θ A c e b L END VIEW SIDE VIEW Notes: (1) All dimensions are in millimeters. Angles in degrees. (2) Complies with JEDEC MS-012. http://onsemi.com 6 P2779A Table 6. ORDERING INFORMATION Part Number Marking Package Type Temperature P2779AF−08−ST P2779AF 8−Pin SOIC, Tube, Pb Free Commercial P2779AF−08−SR P2779AF 8−Pin SOIC, Tape and Reel, Pb Free Commercial P2779AG−08−ST P2779AG 8−Pin SOIC, Tube, Green Commercial P2779AG−08−SR P2779AG 8−Pin SOIC, Tape and Reel, Green Commercial I2779AF−08−ST I2779AF 8−Pin SOIC, Tube, Pb Free Industrial I2779AF−08−SR I2779AF 8−Pin SOIC, Tape and Reel, Pb Free Industrial I2779AG−08−ST I2779AG 8−Pin SOIC, Tube, Green Industrial I2779AG−08−SR I2779AG 8−Pin SOIC, Tape and Reel, Green Industrial P2779AF−08−TT P2779AF 8−Pin TSSOP, Tube, Pb Free Commercial P2779AF−08−TR P2779AF 8−Pin TSSOP, Tape and Reel, Pb Free Commercial P2779AG−08−TT P2779AG 8−Pin TSSOP, Tube, Green Commercial P2779AG−08−TR P2779AG 8−Pin TSSOP, Tape and Reel, Green Commercial I2779AF−08−TT I2779AF 8−Pin TSSOP, Tube, Pb Free Industrial I2779AF−08−TR I2779AF 8−Pin TSSOP, Tape and Reel, Pb Free Industrial I2779AG−08−TT I2779AG 8−Pin TSSOP, Tube, Green Industrial I2779AG−08−TR I2779AG 8−Pin TSSOP, Tape and Reel, Green Industrial ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). 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