ASM3P2579A Peak EMI Reducing Solution Features -The ASM3P2579A uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all digital method. • Generates an EMI optimized clock signal at the output. • Integrated loop filter components. The ASM3P2579A 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.’ • Operates with a 3.3 / 2.5V Supply. • Operating current less than 4mA. • CMOS design. • Input frequency range: 12MHz to 30MHz for 2.5V 12MHz to 30MHz for 3.3V • Generates a 1X low EMI spread spectrum clock of the input frequency. • Spread Spectrum Enable Control. Applications • Frequency deviation: ±1% @ 24MHz The ASM3P2579A is targeted towards all portable devices like MP3 players and digital still cameras. • Available in 6L-TSOP (6L-TSOT-23). Product Description The ASM3P2579A is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. The ASM3P2579A reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of all clock dependent signals. The ASM3P2579A allows significant system cost savings by reducing the number of circuit board layers, ferrite beads and shielding that are traditionally required to pass EMI regulations. Block Diagram Key Specifications Description Specification Supply voltages VDD = 3.3V/2.5V Cycle-to-Cycle Jitter ±200pS (Typ) Output Duty Cycle 45/55% (worst case) Modulation Rate Equation FIN/640 Frequency Deviation ±1% @ 24MHz VDD SSON PLL Modulation XIN Crystal Oscillator XOUT Frequency Divider Feedback Divider Phase Detector Loop Filter VCO Output Divider ModOUT VSS ©2010 SCILLC. All rights reserved. JANUARY 2010 – Rev. 2 Publication Order Number: ASM3P2579/D ASM3P2579A Pin Configuration (6L-TSOP) SSON 1 XOUT 2 XIN / CLKIN 3 ASM3P2579A 6 VSS 5 ModOUT 4 VDD Pin Description Pin# Pin Name Type Description 1 SSON I When SSON is HIGH, the spread spectrum is enabled and when LOW, it turns off the spread spectrum. Connect the pin to ground when Spread Spectrum feature is not required. 2 XOUT O Crystal connection. If using an external reference, this pin must be left unconnected. 3 XIN / CLKIN I Crystal connection or external reference frequency input. This pin has dual functions. It can be connected either to an external crystal or an external reference clock. 4 VDD P Power supply for the entire chip. 5 ModOUT O Spread spectrum clock output. 6 VSS P Ground connection. 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 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) 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 Supply Voltage Min Max Unit 2.375 3.6 V -40 +85 °C TA Operating Temperature (Ambient Temperature) CL Load Capacitance 15 pF CIN Input Capacitance 7 pF Rev. 2 | Page 2 of 7 | www.onsemi.com ASM3P2579A DC Electrical Characteristics for 2.5V Supply Symbol Parameter VIL Min Typ Max Unit V Input low voltage VSS-0.3 0.8 VIH Input high voltage 2.0 VDD+0.3 V IIL Input low current -35 µA IIH Input high current 35 µA IXOL XOUT output low current (@ 0.5V, VDD = 2.5V) 3 mA IXOH XOUT output high current (@ 1.8V, VDD = 2.5V) 3 mA VOL Output low voltage (VDD = 2.5V, IOL = 8mA) VOH Output high voltage (VDD = 2.5V, IOH = 8mA) 0.6 IDD Static supply current 1.1 mA ICC Dynamic supply current (2.5V, 24MHz and no load) 3.5 mA 1.8 1 VDD tON Operating Voltage 2.375 2.5 Power-up time (first locked cycle after power-up) ZOUT V V Output impedance 2.625 V 5 mS Ω 50 Note: 1. XIN / CLKIN is made low. AC Electrical Characteristics for 2.5V Supply Symbol CLKIN ModOUT fd Min Typ Max Unit Input frequency 12 30 MHz Output frequency 12 30 MHz Input Frequency = 12MHz ±1.65 Input Frequency = 30MHz ±0.80 Frequency Deviation % 1 Output rise time (measured from 0.7V to 1.7V) 0.7 1.5 1.9 nS 1 Output fall time (measured from 1.7V to 0.7V) 0.4 1.0 1.1 nS tLH tHL Parameter tJC Jitter (cycle-to-cycle) tD Output duty cycle ±200 45 Note: 1. tLH and tHL are measured into a capacitive load of 15pF. Rev. 2 | Page 3 of 7 | www.onsemi.com 50 pS 55 % ASM3P2579A DC Electrical Characteristics for 3.3V Supply Symbol Parameter VIL Min Typ Max Unit V Input low voltage VSS-0.3 0.8 VIH Input high voltage 2.0 VDD+0.3 V IIL Input low current -35 µA IIH Input high current 35 µA IXOL XOUT output low current (@ 0.4V, VDD = 3.3V) 3 mA IXOH XOUT output high current (@ 2.5V, VDD = 3.3V) 3 mA VOL Output low voltage (VDD = 3.3V, IOL = 8mA) VOH Output high voltage (VDD = 3.3V, IOH = 8mA) 0.4 IDD Static supply current 1.2 mA ICC Dynamic supply current (3.3V, 24MHz and no load) 4.0 mA 1 VDD tON Operating Voltage 2.7 V 3.3 Power-up time (first locked cycle after power-up) ZOUT V 2.5 Output impedance 3.6 V 5 mS Ω 45 Note: 1. XIN / CLKIN is made low. AC Electrical Characteristics for 3.3V Supply Symbol CLKIN ModOUT fd Min Typ Max Unit Input frequency 12 30 MHz Output frequency 12 30 MHz Input Frequency = 12MHz ±1.65 Input Frequency = 30MHz ±0.80 Frequency Deviation % 1 Output rise time (measured from 0.8 to 2.0V) 0.5 1.4 1.7 nS 1 Output fall time (measured at 2.0V to 0.8V) 0.4 1.0 1.2 nS tLH tHL Parameter tJC Jitter (cycle-to-cycle) tD Output duty cycle ±200 45 Note: 1. tLH and tHL are measured into a capacitive load of 15pF. Rev. 2 | Page 4 of 7 | www.onsemi.com 50 pS 55 % ASM3P2579A Typical Crystal Specifications Fundamental AT cut parallel resonant crystal Nominal frequency 14.31818MHz Frequency tolerance ± 50 ppm or better at 25°C Operating temperature range -25°C to +85°C Storage temperature -40°C to +85°C Load capacitance(CP) 18pF Shunt capacitance 7pF maximum ESR 25 Ω Note: Note: CL is Load Capacitance and Rx is used to prevent oscillations at overtone frequency of the Fundamental frequency. Typical Crystal Interface Circuit R Rx Crystal CL CL CL = 2*(CP – CS), Where CP = Load capacitance of crystal CS = Stray capacitance due to CIN, PCB, Trace etc. Typical Application Schematic VDD C1 0.1µF C2 2.2µF VDD ASM3P2579A Rs ModOUT VSS Rev. 2 | Page 5 of 7 | www.onsemi.com ModOUT Clock ASM3P2579A Package Information 6L-TSOP Dimensions Symbol Inches Min A Millimeters Max Min Max 0.04 1.00 A1 0.00 0.004 0.00 0.10 A2 0.033 0.036 0.84 0.90 b 0.012 0.02 0.30 0.50 H 0.005 BSC 0.127 BSC D 0.114 BSC 2.90 BSC B 0.06 BSC 1.60 BSC e 0.0374 BSC 0.950 BSC C 0.11 BSC 2.80 BSC L 0.0118 0.02 0.30 0.50 θ 0° 4° 0° 4° Rev. 2 | Page 6 of 7 | www.onsemi.com ASM3P2579A Ordering Information Part Number Marking ASM3I2579AF-06OR S5L Package Type Temperature 6L-TSOP (6L-TSOT-23), TAPE & REEL, Pb Free -40°C to +85°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. Licensed under US Patent #5,488,627 and #5,631,921. Note: This product utilizes US Patent #6,646,463 Impedance Emulator Patent issued to PulseCore Semiconductor, dated 11-11-2003. ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes 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. 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