DATASHEET ICS7151 SPREAD SPECTRUM CLOCK GENERATOR Description Features The ICS7151-10, -20, -40, and -50 are clock generators for EMI (Electro Magnetic Interference) reduction (see below for frequency ranges and multiplier ratios). Spectral peaks can be attenuated by slightly modulating the oscillation frequency. Both down and center spread profiles are selectable. Down spread maintains an average frequency less than an unspread clock, and will not exceed the maximum frequency of an unspread clock. • • • • • Operating voltage of 3.3 V ±0.3 V Packaged in 8-pin SOIC Pb (lead) free package, RoHS compliant Input frequency range of 16.5 to 33.4 MHz Output frequency ranges of 8.3 to 16.7 MHz, 16.5 to 33.4 MHz, 33.3 to 66.7 MHz, 66.6 to 133.4 MHz • Provides a spread spectrum clock output (±0.5%, ±1.5% center spread; -1.0%, -3.0% down spread) • Multiplication rates of x1/2, x1, x2, and x4 • Advanced, low-power CMOS process Block Diagram VDD S1:0 2 PLL Clock Synthesis and Spread Spectrum Circuitry ENS XIN CKOUT Clock Buffer/ Crystal Ocsillator XOUT External caps required with crystal for accurate tuning of the clock GND Product Lineup Product Input Frequency Range Multiplier Ratio Output Frequency Range ICS7151M-10, ICS7151MI-10 16.5 MHz to 33.4 MHz X1 16.5 MHz to 33.4 MHz ICS7151M-20, ICS7151MI-20 16.5 MHz to 33.4 MHz X2 33.3 MHz to 66.7 MHz ICS7151M-40, ICS7151MI-40 16.5 MHz to 33.4 MHz X4 66.6 MHz to 133.4 MHz ICS7151M-50, ICS7151MI-50 16.5 MHz to 33.4 MHz X1/2 8.3 MHz to 16.7 MHz IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR 1 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG Pin Assignment Spread Direction and Percentage Select Table XIN 1 8 XOUT GND 2 7 VDD S0 3 6 ENS S1 4 5 CKOUT 8 pin (150 mil) SOIC S1 Pin 4 (note1) S0 Pin 3 (note1) Spread Direction Spread Percentage (%) 0 0 Center ±1.5 0 1 Center ±0.5 1 0 Down -1.0 1 1 Down -3.0 ENS (note 2) Spread Spectrum 0 OFF 1 ON Notes: 1. The modulation rate varies with input frequency. 2. Spread will default to ON when ENS pin is left open. Pin Descriptions Pin Number Pin Name Pin Type Pin Description 1 XIN Input Resonator connection pin/clock input pin. 2 GND Power Connect to ground. 3 S0 Input Select pin 0. Modulation rate setting pin. 4 S1 Input Select pin 1. Modulation rate setting pin. 5 CKOUT Output 6 ENS Input Modulation enable setting pin. Internal pull-up resistor. 7 VDD Power Connect to +3.3 V. 8 XOUT Output Resonator connection pin. Modulated clock output pin. IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR 2 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG External Components In the equation, CL is the crystal load capacitance. So, for a crystal with a 16 pF load capacitance, two 20 pF [(16-6) x 2] capacitors should be used. The ICS7151 requires a minimum number of external components for proper operation. Spread Spectrum Profile Decoupling Capacitor The ICS7151 low EMI clock generator uses a triangular frequency modulation profile for optimal down stream tracking of zero delay buffers and other PLL devices. The frequency modulation amplitude is constant with variations of the input frequency. A decoupling capacitor of 0.01µF must be connected between GND and VDD on pin 7, as close to this pin as possible. For optimum device performance, the decoupling capacitor should be mounted on the component side of the PCB. Avoid the use of vias in the decoupling circuit. Series Termination Resistor Series termination should be used on the clock output. To series terminate a 50Ω trace (a commonly used trace impedance) place a 27Ω resistor in series with the clock line, as close to the clock output pin as possible. The nominal impedance of the clock output is 25Ω. Frequency Modulation Rate PCB Layout Recommendations For optimum device performance and lowest output phase noise, the following guidelines should be observed. Time 1) The 0.01µF decoupling capacitor should be mounted on the component side of the board as close to the VDD pin as possible. No vias should be used between the decoupling capacitor and VDD pin. The PCB trace to VDD pin should be kept as short as possible, as should the PCB trace to the ground via. 2) To minimize EMI, the 27Ω series termination resistor (if needed) should be placed close to the clock output. 3) An optimum layout is one with all components on the same side of the board, minimizing vias through other signal layers. Other signal traces should be routed away from the ICS7151. This includes signal traces just underneath the device, or on layers adjacent to the ground plane layer used by the device. Crystal Information The crystal used should be a fundamental mode (do not use third overtone), parallel resonant. Crystal capacitors should be connected from pins X1 to ground and X2 to ground to optimize the initial accuracy. The value of these capacitors is given by the following equation: Crystal caps (pF) = (CL - 6) x 2 IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR 3 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG Absolute Maximum Ratings Stresses above the ratings listed below can cause permanent damage to the ICS7151. These ratings, which are standard values for IDT commercially rated parts, are stress ratings only. Functional operation of the device at these or any other conditions above those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can affect product reliability. Electrical parameters are guaranteed only over the recommended operating temperature range. Item Rating Supply Voltage, VDD 7V All Inputs and Outputs (referenced to GND) -0.5 V to VDD+0.5 V Ambient Operating Temperature -40 to +85° C Storage Temperature -55 to +125° C Junction Temperature -40 to +125° C Soldering Temperature 260° C Overshoot (VIOVER) VDD + 1.0 V (tOVER < 50 ns) Undershoot (VIUNDER) GND - 1.0 V (tUNDER < 50 ns) Overshoot/Undershoot tUNDER < 50 ns VIOVER < VDD + 1.0 V VDD Input pin tOVER < 50 ns GND VIUNDER < GND - 1.0 V Recommended Operation Conditions Parameter Min. Ambient Operating Temperature -40 Power Supply Voltage (measured in respect to GND) +3.0 IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR 4 Typ. 3.3 Max. Units +85 °C 3.6 V ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG DC Electrical Characteristics Unless stated otherwise, VDD = 3.3 V ±0.3 V, Ambient Temperature -40 to +85° C Parameter Symbol Conditions Min. Typ. Max. Units 3.0 3.3 3.6 V 10 20 mA Operating Voltage VDD Supply Current IDD No load, at 3.3 V Input High Voltage VIH XIN, S0, S1, ENS VDDx0.8 VDD + 0.3 V Input Low Voltage VIL XIN, S0, S1, ENS 0.0 VDDx0.20 V Output High Voltage VOH CKOUT, IOH = -4 mA Output Low Voltage VOL CKOUT, IOL = 4 mA 0.4 V Input Capacitance CIN XIN, S0, S1, ENS 16 pF CKOUT, 8.3 to 66.7 MHz 15 pF CKOUT, 66.7 to 100 MHz 10 pF CKOUT, 100 to 133.4 MHz 7 pF 400 kΩ Load Capacitance Input Pull-up Resistor CL ENS RPU VDD-0.5 V 100 240 AC Electrical Characteristics Unless stated otherwise, VDD = 3.3 V ±0.3 V, Ambient Temperature -40 to +85° C Parameter Symbol Conditions Max. Units 16.5 33.4 MHz 16.5 33.4 MHz CKOUT, Multiply by 1 (ICS7151-10) 16.5 33.4 MHz CKOUT, Multiply by 2 (ICS7151-20) 33.3 66.7 MHz CKOUT, Multiply by 4 (ICS7151-40) 66.6 133.4 MHz CKOUT, 2-frequency division (ICS7151-50) 8.3 16.7 MHz XIN, 16.5 to 33.4 MHz 40 60 % CKOUT, 1.5 V 40 60 % CKOUT, 0.4 to 2.4 V, CL = 15 pF 0.5 3.0 V/ns Input Crystal Frequency Input Clock Frequency Output Frequency fIN fOUT Input Clock Duty Cycle Output Clock Duty Cycle tDCC Output Slew Rate IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR 5 Min. Typ. 50 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR Parameter SSCG Symbol Cycle to Cycle Jitter tJC Power-up Time Modulation Frequency fMOD Conditions Min. Typ. Max. Units No load, spread off (ICS7151-10, -20) 100 ps No load, spread off (ICS7151-40) 150 ps No load, spread off (ICS7151-50) 200 ps 5 ms PLL lock-time from power-up to 1% of final value 2 CKOUT 33 kHz Input Frequency (fIN = 1/tIN) tIN 0.8 VDD XIN Output Slew Rate 2.4 V 0.4 V CKOUT tr tf SR = (2.4 - 0.4) /tr, SR = (2.4 - 0.4) /tf Thermal Characteristics 8 SOIC Parameter Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR Symbol Conditions Min. Typ. Max. Units θJA Still air 150 ° C/W θJA 1 m/s air flow 140 ° C/W θJA 3 m/s air flow 120 ° C/W 40 ° C/W θJC 6 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG Package Outline and Package Dimensions (8-pin SOIC, 150 Mil. Body) Package dimensions are kept current with JEDEC Publication No. 95 8 Millimeters Symbol E A A1 B C D E e H h L α H INDEX AREA 1 2 D A Min Inches Max Min 1.35 1.75 0.10 0.25 0.33 0.51 0.19 0.25 4.80 5.00 3.80 4.00 1.27 BASIC 5.80 6.20 0.25 0.50 0.40 1.27 0° 8° Max .0532 .0688 .0040 .0098 .013 .020 .0075 .0098 .1890 .1968 .1497 .1574 0.050 BASIC .2284 .2440 .010 .020 .016 .050 0° 8° h x 45 A1 C -Ce B SEATING PLANE L .10 (.004) IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR C 7 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG Ordering Information Part / Order Number Marking Shipping Packaging Package Temperature 7151M-10LF 7151M-10LFT 7151M-20LF 7151M-20LFT 7151M-40LF 7151M-40LFT 7151M-50LF 7151M-50LFT 7151MI-10LF 7151MI-10LFT 7151MI-20LF 7151MI-20LFT 7151MI-40LF 7151MI-40LFT 7151MI-50LF 7151MI-50LFT 51M-10LF 51M-10LF 51M-20LF 51M-20LF 51M-40LF 51M-40LF 51M-50LF 51M-50LF 51MI10LF 51MI10LF 51MI20LF 51MI20LF 51MI40LF 51MI40LF 51MI50LF 51MI50LF Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel Tubes Tape and Reel 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 8-pin SOIC 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C 0 to +70° C -40 to +85° C -40 to +85° C -40 to +85° C -40 to +85° C -40 to +85° C -40 to +85° C -40 to +85° C -40 to +85° C “LF” suffix to the part number are the Pb-Free configuration and are RoHS compliant. While the information presented herein has been checked for both accuracy and reliability, Integrated Device Technology (IDT) assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary environmental requirements are not recommended without additional processing by IDT. IDT reserves the right to change any circuitry or specifications without notice. IDT does not authorize or warrant any IDT product for use in life support devices or critical medical instruments. IDT™ / ICS™ SPREAD SPECTRUM CLOCK GENERATOR 8 ICS7151 REV J 051310 ICS7151 SPREAD SPECTRUM CLOCK GENERATOR SSCG Innovate with IDT and accelerate your future networks. Contact: www.IDT.com For Sales For Tech Support 800-345-7015 408-284-8200 Fax: 408-284-2775 www.idt.com/go/clockhelp Corporate Headquarters Integrated Device Technology, Inc. www.idt.com © 2006 Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice. IDT and the IDT logo are trademarks of Integrated Device Technology, Inc. Accelerated Thinking is a service mark of Integrated Device Technology, Inc. All other brands, product names and marks are or may be trademarks or registered trademarks used to identify products or services of their respective owners. Printed in USA