September 2003 ASM3P2185B rev 1.0 EMI Reduction IC Features The ASM3P2185B reduces electromagnetic interference FCC approved method of EMI attenuation. (EMI) at the clock source, allowing system wide EMI Provides up to 15dB EMI reduction. Generates a 1X low EMI spread spectrum clock of the input frequency. reduction for all the down stream clocks and data dependent signals. The ASM3P2185B allows significant system cost savings by reducing the number of circuit Input frequency range: 25MHz to 50 MHz. Internal loop filter minimizes external components and board space. board layers, ferrite beads, shielding, and other passive components that are traditionally required to pass EMI regulations. Down Spread and Center Spread. 2 spread frequency deviation selections: -1.25% and ± 0.8%. The ASM3P2185B uses the most efficient and optimized modulation profile approved by the FCC and is Low inherent cycle-to-cycle jitter. implemented in a proprietary all digital method. 3.3V operating voltage range. TTL or CMOS compatible inputs and outputs. The ASM3P2185B modulates the output of a single PLL Low power CMOS design. Supports notebook VGA and other LCD timing controller applications. Products are available for industrial temperature range. 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 Available in 8-pin SOIC and TSSOP. EMI by increasing a signal’s bandwidth is called ‘spread spectrum clock generation’. Product Description The ASM3P2185B is a versatile spread spectrum frequency modulator designed specifically for a wide range of input clock frequencies from 25MHz to 50MHz. The ASM3P2185B can generate an EMI reduced clock from an OSC or a system generated clock. Applications The ASM3P2185B is targeted towards EMI management for memory and LVDS interfaces in mobile graphic chipsets and high-speed digital applications such as PC peripheral devices, consumer electronics, and embedded controller systems. Block Diagram SS% VDD PLL Modulation XIN Crystal Oscillator Frequenc y XOUT Feedback Divider Phase Detector Loop Filter VCO Output Divider ModOUT VSS Alliance Semiconductor 2575, Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com Notice: The information in this document is subject to change without notice. September 2003 ASM3P2185B rev 1.0 Pin Configuration XIN 1 XOUT 2 8 NC 7 NC ASM3P2185B GND 3 6 VDD SS% 4 5 ModOUT Pin Description Pin# Pin Name Type Description 1 XIN I 2 XOUT I 3 GND P Ground to entire chip. 4 SS% I Spread range select. Digital logic input used to select frequency deviation (Refer Spread Deviation Table). This pin has an internal pull-up resistor. 5 ModOUT O Spread spectrum low EMI output. 6 VDD P Power supply for the entire chip (3.3V). 7 NC No Connect. 8 NC No Connect. 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. Crystal connection. Input connection for an external crystal. If using an external reference, this pin must be left unconnected. Spread Deviation Selection Table SS% (pin 4) Spread Deviation (%) 0 - 1.25 1 ± 0.8% EMI Reduction IC Notice: The information in this document is subject to change without notice. 2 of 7 September 2003 ASM3P2185B rev 1.0 Absolute Maximum Ratings Symbol VDD, VIN Parameter Voltage on any pin with respect to GND Rating Unit -0.5 to + 7.0 V TSTG Storage temperature -65 to +125 °C TA Operating temperature 0 to 70 °C Note: These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliability. 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 - - -35 µA IIH Input high current - - 35 µA IXOL XOUT Output low current (@ 0.4V, VDD = 3.3V) - TBD - mA IXOH XOUT Output high current (@ 2.5V, VDD = 3.3V) - TBD - mA VOL Output low voltage (VDD = 3.3V, IOL = 20mA) - - 0.4 V VOH Output high voltage (VDD = 3.3V, IOH = 20mA) 2.5 - - V 8.46 12 17.78 mA ICC IDD Dynamic supply current Normal mode (3.3V and 10pF loading) Static supply current Standby mode VDD Operating voltage tON ZOUT 0.6 mA 2.7 3.3 3.7 V Power up time (first locked clock cycle after power up) - 0.18 - mS Clock out impedance - 50 - Ω EMI Reduction IC Notice: The information in this document is subject to change without notice. 3 of 7 September 2003 ASM3P2185B rev 1.0 AC Electrical Characteristics Symbol Parameter Min Typ Max Unit XIN Input frequency 25 - 50 MHz ModOUT Output frequency 25 - 50 MHz tLH* Output rise time (measured at 0.8V to 2.0V) 1.2 1.32 1.4 ns tHL* Output fall time (measured at 2.0V to 0.8V) 0.8 0.9 1.0 ns tJC Jitter (cycle to cycle) - - 360 ps TD Output duty cycle 45 50 55 % tLH and tHL are measured into a capacitive load of 15pF EMI Reduction IC Notice: The information in this document is subject to change without notice. 4 of 7 September 2003 ASM3P2185B rev 1.0 Package Information 8-Pin SOIC H E D A2 A C θ e A1 B Symbol Dimensions in inches D L Dimensions in millimeters Min Max Min Max A 0.057 0.071 1.45 1.80 A1 0.004 0.010 0.10 0.25 A2 0.053 0.069 1.35 1.75 B 0.012 0.020 0.31 0.51 C 0.004 0.01 0.10 0.25 D 0.186 0.202 4.72 5.12 E 0.148 0.164 3.75 4.15 e 0.050 BSC 1.27 BSC H 0.224 0.248 5.70 6.30 L 0.012 0.028 0.30 0.70 0° 8° 0° 8° EMI Reduction IC Notice: The information in this document is subject to change without notice. 5 of 7 September 2003 ASM3P2185B rev 1.0 8-Pin TSSOP H E D A2 A C θ e A1 L B Dimensions in inches Symbol Min A 0.047 A1 0.002 0.006 0.05 0.15 A2 0.031 0.041 0.80 1.05 B 0.007 0.012 0.19 0.30 C 0.004 0.008 0.09 0.20 D 0.114 0.122 2.90 3.10 E 0.169 0.177 4.30 4.50 e Max Dimensions in millimeters Min Max 1.10 0.026 BSC 0.65 BSC H 0.244 0.260 6.20 6.60 L 0.018 0.030 0.45 0.75 θ 0° 8° 0° 8° EMI Reduction IC Notice: The information in this document is subject to change without notice. 6 of 7 September 2003 ASM3P2185B rev 1.0 Copyright © Alliance Semiconductor All Rights Reserved Preliminary Information Part Number: ASM3P2185B Document Version: v1.0 Alliance Semiconductor Corporation 2595, Augustine Drive, Santa Clara, CA 95054 Tel# 408-855-4900 Fax: 408-855-4999 www.alsc.com © Copyright 2003 Alliance Semiconductor Corporation. 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Alliance does not authorize its products for use as critical components in life-supporting systems where a malfunction or failure may reasonably be expected to result in significant injury to the user, and the inclusion of Alliance products in such life-supporting systems implies that the manufacturer assumes all risk of such use and agrees to indemnify Alliance against all claims arising from such use. EMI Reduction IC Notice: The information in this document is subject to change without notice. 7 of 7