ASM3P2579A

ASM3P2579A Peak EMI Reducing Solution Features • Generates an EMI optimized clock signal at the output. • Integrated loop filter components. • 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. • Frequency deviation: ±1% @ 24MHz • Available in 6L-TSOP (6L-TSOT-23). -The ASM3P2579A uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all digital method. 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.’ Applications The ASM3P2579A is targeted towards all portable devices like MP3 players and digital still cameras. 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. Key Specifications Description Supply voltages Cycle-to-Cycle Jitter Output Duty Cycle Modulation Rate Equation Frequency Deviation Specification VDD = 3.3V/2.5V ±200pS (Typ) 45/55% (worst case) FIN/640 ±1% @ 24MHz Block Diagram VDD SSON Modulation XIN Crystal Oscillator XOUT Frequency Divider Feedback Divider PLL 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 XOUT XIN / CLKIN 1 2 3 6 VSS ModOUT VDD ASM3P2579A 5 4 Pin Description Pin# 1 2 3 4 5 6 Pin Name SSON XOUT XIN / CLKIN VDD ModOUT VSS Type I O I P O P Description 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. Crystal connection. If using an external reference, this pin must be left unconnected. 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. Power supply for the entire chip. Spread spectrum clock output. Ground connection. Absolute Maximum Ratings Symbol VDD, VIN TSTG Ts TJ TDV Storage temperature Parameter Rating -0.5 to +4.6 -65 to +125 260 150 2 Unit V ° C ° C ° C KV Voltage on any pin with respect to Ground Max. Soldering Temperature (10 sec) Junction Temperature 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 TA CL CIN Supply Voltage Operating Temperature (Ambient Temperature) Load Capacitance Input Capacitance Description Min 2.375 -40 Max 3.6 +85 15 7 Unit V ° C pF pF Rev. 2 | Page 2 of 7 | www.onsemi.com ASM3P2579A DC Electrical Characteristics for 2.5V Supply Symbol Parameter VIL VIH IIL IIH IXOL IXOH VOL VOH IDD ICC VDD tON ZOUT Input low voltage Input high voltage Input low current Input high current XOUT output low current (@ 0.5V, VDD = 2.5V) XOUT output high current (@ 1.8V, VDD = 2.5V) Output low voltage (VDD = 2.5V, IOL = 8mA) Output high voltage (VDD = 2.5V, IOH = 8mA) Static supply current Operating Voltage Power-up time (first locked cycle after power-up) Output impedance 50 1 Min VSS-0.3 2.0 Typ Max 0.8 VDD+0.3 -35 35 Unit V V µA µA mA mA 3 3 0.6 1.8 1.1 3.5 2.375 2.5 2.625 5 V V mA mA V mS Dynamic supply current (2.5V, 24MHz and no load) Note: 1. XIN / CLKIN is made low. AC Electrical Characteristics for 2.5V Supply Symbol CLKIN ModOUT fd tLH tHL 1 1 Parameter Input frequency Output frequency Input Frequency = 12MHz Frequency Deviation Input Frequency = 30MHz Output rise time (measured from 0.7V to 1.7V) Output fall time (measured from 1.7V to 0.7V) Jitter (cycle-to-cycle) Output duty cycle Min 12 12 Typ Max 30 30 Unit MHz MHz % ±1.65 ±0.80 0.7 0.4 1.5 1.0 ±200 45 50 55 1.9 1.1 nS nS pS % tJC tD Note: 1. tLH and tHL are measured into a capacitive load of 15pF. Rev. 2 | Page 3 of 7 | www.onsemi.com ASM3P2579A DC Electrical Characteristics for 3.3V Supply Symbol Parameter VIL VIH IIL IIH IXOL IXOH VOL VOH IDD ICC VDD tON ZOUT Input low voltage Input high voltage Input low current Input high current XOUT output low current (@ 0.4V, VDD = 3.3V) XOUT output high current (@ 2.5V, VDD = 3.3V) Output low voltage (VDD = 3.3V, IOL = 8mA) Output high voltage (VDD = 3.3V, IOH = 8mA) Static supply current Operating Voltage Power-up time (first locked cycle after power-up) Output impedance 45 1 Min VSS-0.3 2.0 Typ Max 0.8 VDD+0.3 -35 35 Unit V V µA µA mA mA 3 3 0.4 2.5 1.2 4.0 2.7 3.3 3.6 5 V V mA mA V mS Dynamic supply current (3.3V, 24MHz and no load) Note: 1. XIN / CLKIN is made low. AC Electrical Characteristics for 3.3V Supply Symbol CLKIN ModOUT fd tLH tHL 1 1 Parameter Input frequency Output frequency Input Frequency = 12MHz Frequency Deviation Input Frequency = 30MHz Output rise time (measured from 0.8 to 2.0V) Output fall time (measured at 2.0V to 0.8V) Jitter (cycle-to-cycle) Output duty cycle Min 12 12 Typ Max 30 30 Unit MHz MHz % ±1.65 ±0.80 0.5 0.4 1.4 1.0 ±200 45 50 55 1.7 1.2 nS nS pS % tJC tD Note: 1. tLH and tHL are measured into a capacitive load of 15pF. Rev. 2 | Page 4 of 7 | www.onsemi.com ASM3P2579A Typical Crystal Specifications Fundamental AT cut parallel resonant crystal Nominal frequency Frequency tolerance Operating temperature range Storage temperature Load capacitance(CP) Shunt capacitance ESR 14.31818MHz ± 50 ppm or better at 25° C -25° to +85° C C -40° to +85° C C 18pF 7pF maximum 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 Crystal Rx 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 ModOUT Clock VSS Rev. 2 | Page 5 of 7 | www.onsemi.com ASM3P2579A Package Information 6L-TSOP Dimensions Symbol Min A A1 A2 b H D B e C L θ 0.00 0.033 0.012 Inches Max 0.04 0.004 0.036 0.02 Millimeters Min Max 1.00 0.00 0.84 0.30 0.127 BSC 2.90 BSC 1.60 BSC 0.950 BSC 2.80 BSC 0.30 0° 0.50 4° 0.10 0.90 0.50 0.005 BSC 0.114 BSC 0.06 BSC 0.0374 BSC 0.11 BSC 0.0118 0° 0.02 4° Rev. 2 | Page 6 of 7 | www.onsemi.com ASM3P2579A Ordering Information Part Number ASM3I2579AF-06OR Marking S5L Package Type 6L-TSOP (6L-TSOT-23), TAPE & REEL, Pb Free Temperature -40° to +85° C 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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