ICS7151A-50 Spread Spectrum Clock Generator Description Features The ICS7151A-50 is a clock generator for EMI (Electromagnetic Interference) reduction. Spectral peaks are attenuated by modulating the system clock frequency. Down or center spread profiles are selectable. Down spread will not exceed the maximum frequency of an unspread clock, and center spread does not change the average operating frequency of the system • • • • • • ICS offers many other clocks for computers and computer peripherals. Consult ICS when you need to remove crystals and oscillators from your board. • Multiplication rate of x1/2 • Advanced, low-power CMOS process • Pin compatible with the Fujitsu MB88151-500 Operating voltage of 3.3 V ±0.3 V Packaged in 8-pin SOIC Available in Pb (lead) free package Input frequency range of 16.5 to 33.4 MHz Output frequency ranges of 8.3 to 16.7 MHz Provides a spread spectrum clock output (±0.5%, ±1.5% center spread; -1.0%, -3.0% down spread) Block Diagram VDD S1:0 2 PLL Clock Synthesis and Spread Spectrum Circuitry ENS XIN CKOUT Clock Buffer/ Crystal Ocsillator XOUT GND External caps required with crystal for accurate tuning of the clock 1 MDS 7151A-50 A Integrated Circuit Systems, Inc. ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator Pin Assignment Spread Direction and Percentage Select Table XIN 1 8 XOUT GND 2 7 S0 3 S1 4 VDD S1 Pin 4 S0 Pin 3 Spread Direction Spread Percentage (%) 6 ENS 0 0 Center ±1.5 5 CKOUT 0 1 Center ±0.5 1 0 Down -1.0 1 1 Down -3.0 8 pin (150 mil) SOIC ENS (note 1) Modulation 0 No Modulation 1 Modulation Notes: 1. Pin 1 has a pull-up resistor. Pin Descriptions Pin Number Pin Name Pin Type 1 XIN Input Crystal pin/clock input pin. 2 GND Power Connect to ground. 3 S0 Input Select pin 0. Spread modulation select. 4 S1 Input Select pin 1. Spread modulation select. 5 CKOUT Output 6 ENS Input Modulation enable. Internal pull-up resistor. 7 VDD Power Connect to +3.3 V. 8 XOUT Output Crystal connection pin. Clock output. 2 MDS 7151A-50 A Integrated Circuit Systems, Inc. Pin Description ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator External Components traces just underneath the device, or on layers adjacent to the ground plane layer used by the device. The ICS7151A-50 requires a minimum number of external components for proper operation. Crystal Information A decoupling capacitor of 0.01µF must be connected between GND and VDD on pins 2 and 7, as close to these pins 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. PCB Layout Recommendations For optimum device performance and lowest output phase noise, the following guidelines should be observed. 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. 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 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. Spread Spectrum Profile The ICS7151A-50 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. Modulation Rate Frequency Decoupling Capacitor Time 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 ICS7151A-50. This includes signal 3 MDS 7151A-50 A Integrated Circuit Systems, Inc. ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator Absolute Maximum Ratings Stresses above the ratings listed below can cause permanent damage to the ICS7151A-50. These ratings, which are standard values for ICS 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 -0.5 to 4.0 V 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 GND VIUNDER < GND - 1.0 V tOVER < 50 ns Recommended Operation Conditions Parameter Min. Ambient Operating Temperature -40 Power Supply Voltage (measured in respect to GND) +3.0 3.3 Max. Units +85 °C 3.6 V 4 MDS 7151A-50 A Integrated Circuit Systems, Inc. Typ. ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator DC Electrical Characteristics Unless stated otherwise, VDD = 3.3 V ±0.3 V, Ambient Temperature -40 to +85°C Parameter Symbol Operating Voltage VDD Supply Current IDD Conditions Min. Typ. Max. Units 3.0 3.3 3.6 V 10 14 mA 16.5 33.4 MHz No load, at 3.3 V, output = 24 MHz Input Frequency Input High Voltage VIH XIN, S0, S1, ENS VDD * 0.8 VDD + 0.3 V Input Low Voltage VIL XIN, S0, S1, ENS 0.0 VDD * 0.20 V Output High Voltage VOH CKOUT, IOH = -4 mA 2.0 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 CL Input Pull-up Resistor ENS RPU 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 Min. Typ. Max. Units Oscillation Frequency fX Fundamental oscillation 16.5 33.4 MHz Input Frequency fIN XIN 16.5 33.4 MHz CKOUT, 2-frequency division 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, load capacitance 15 pF 0.5 TBD 3.0 V/ns TBD 200 ps 5 ms Output Frequency fOUT Input Clock Duty Cycle Output Clock Duty Cycle tDCC Output Slew Rate 50 Cycle to Cycle Jitter tJC No load, standard deviation Lock Time tLK CKOUT 2 CKOUT=TBD 33 Modulation Frequency fMOD 5 MDS 7151A-50 A Integrated Circuit Systems, Inc. kHz ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator Input Frequency (fIN = 1/tIN) tIN 0.8 VDD CKIN 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 Parameter Symbol Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case 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 MDS 7151A-50 A Integrated Circuit Systems, Inc. Conditions ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator Package Outline and Package Dimensions (8-pin SOIC, 150 Mil. Body) Package dimensions are kept current with JEDEC Publication No. 95 Millimeters 8 Symbol E Min A A1 B C D E e H h L α H INDEX AREA 1 2 D 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° *For reference only. Controlling dimensions in mm. A h x 45 A1 C -Ce SEATING PLANE B L .10 (.004) C Ordering Information Part / Order Number Marking Shipping Packaging Package Temperature ICS7151AM-50 ICS7151AM-50T ICS7151AM-50LF ICS7151AM-50LFT ICS7151AMI-50 ICS7151AMI-50T ICS7151AMI-50LF ICS7151AMI-50LFT 7151AM50 7151AM50 151AM50L 151AM50L 151AMI50 151AMI50 51AMI50L 51AMI50L 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 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 Parts that are ordered with a "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 Circuit Systems (ICS) 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 ICS. ICS reserves the right to change any circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or critical medical instruments. 7 MDS 7151A-50 A Integrated Circuit Systems, Inc. ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com ICS7151A-50 Spread Spectrum Clock Generator Revision History Rev. Originator Date A J. Sarma 10/20/05 Description of Change Rev A; new device/datasheet. 8 MDS 7151A-50 A Integrated Circuit Systems, Inc. ● 525 Race Street, San Jose, CA 95126 Revision 102005 ● tel (408) 297-1201 ● www.icst.com