ASM3P2108A Peak EMI Reducing Solution Features • FCC approved method of EMI attenuation. • Generates a 1X low EMI spread spectrum clock of the input frequency. • Input frequency range: 25MHz to 45MHz. • Internal loop filter minimizes external components and board space. • Frequency deviation: - 1.3%( Typ) @ 32MHz. • Low cycle-to-cycle jitter. • 5.0V ± 5% operating voltage range. • TTL or CMOS compatible outputs. • Available in 8-pin SOIC Package. Product Description The ASM3P2108A is a versatile spread spectrum frequency modulator designed specifically for input clock frequencies from 25MHz to 45MHz. The ASM3P2108A can generate an EMI reduced clock from crystal, ceramic resonator, or system clock. The ASM3P2108A reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of down stream clock and data dependent signals. The ASM3P2108A allows significant system cost savings Block Diagram by reducing the number of circuit board layers ferrite beads, shielding and other passive components that are traditionally required to pass EMI regulations. The ASM3P2108A uses the most efficient and optimized modulation profile approved by the FCC and is implemented in a proprietary all digital method. The ASM3P2108A 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.’ Applications The ASM3P2108A is targeted towards EMI management for high speed digital applications such as PC peripheral devices, consumer electronics and embedded controller systems. VDD PLL Modulation XIN Crystal Oscillator XOUT Frequency Divider Feedback Divider Phase Detector Loop Filter VCO Output Divider CLOCKOUT GND ©2010 SCILLC. All rights reserved. OCTOBER 2010 – Rev. 2 Publication Order Number: ASM3P2108/D ASM3P2108A Pin Configuration 8 NC XIN / CLKIN 1 XOUT 2 ASM3P2108A GND 3 NC 4 7 NC 6 VDD 5 CLOCKOUT Pin Description Pin# Pin Name Type Description 1 XIN / CLKIN I Crystal connection or external reference frequency input. This pin has dual functions. It can be connected to either 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 GND P Ground to entire chip. 4 NC - No connect. 5 CLOCKOUT O Spread spectrum low EMI output. 6 VDD P Power supply for the entire chip (5V). 7 NC - No connect. 8 NC - No connect. Absolute Maximum Ratings Symbol VDD, VIN TSTG Parameter Rating Unit Voltage on any pin with respect to Ground -0.5 to +7.0 V Storage temperature -65 to +125 °C TA Operating temperature 0 to 70 °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 Symbol VDD Parameter Min Max Unit Supply Voltage with respect to VSS 4.75 5.25 V TA Operating temperature -40 +85 °C CL Load Capacitance 15 pF CIN Input Capacitance 7 pF Rev. 1 | Page 2 of 5 | www.onsemi.com ASM3P2108A DC Electrical Characteristics Symbol Parameter Min Typ Max Unit VIL Input low voltage GND – 0.3 0.8 V VIH Input high voltage 2.0 VDD + 0.3 V IIL Input low current 44 µA IIH Input high current 66 µA IXOL XOUT output low current (@ 0.4, VDD = 5V) 3 mA IXOH XOUT output high current (@2.5V, VDD = 5V) 3 mA VOL Output low voltage (VDD = 5V, IOL = 20mA) VOH 2.5 IDD Output high voltage (VDD = 5V, IOH = 20mA) Dynamic supply current normal mode (5V, 32MHz and 15pF loading) Static supply current standby mode VDD Operating voltage 4.75 tON Power up time (first locked clock cycle after power up) ICC ZOUT 0.4 V fIN MODOUT Parameter 25 Output frequency 25 tLH* tHL* Output fall time (measured at 2.0V to 0.8V) fd Min Input frequency Input Frequency = 25MHz Frequency Deviation Input Frequency = 45MHz Output rise time (measured at 0.8V to 2.0V) tJC Jitter (cycle to cycle) tD Output duty cycle 45 * VDD = +5V, Input Frequency = 32MHz, tLH and tHL are measured into a capacitive load of 15pF Rev. 1 | Page 3 of 5 | www.onsemi.com 40 mA 40 µA 5.0 Clock out impedance AC Electrical Characteristics Symbol V 5.25 V 0.18 mS 50 Ω Typ Max Unit 45 MHz 45 MHz -1.98 -0.60 440 pS 300 pS 50 % ±360 pS 55 % ASM3P2108A 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° 0.41 1.27 0° 8° Rev. 1 | Page 4 of 5 | www.onsemi.com ASM3P2108A Ordering Codes Part Number ASM3P2108AF-08SR Marking AEG Package Temperature 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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