Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline October 2000 Order Number: 249234-001
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® Information in this document is provided in connection with Intel products. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document.
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® 1.0 Introduction As microprocessor amperage and speeds increase, the ability to contain the corresponding electromagnetic radiation becomes more difficult. Frequencies generated by the Pentium ® 4 processor will be in the low gigahertz (GHz) range, which will impact both the system design and the electromagnetic interference (EMI) test methodology.
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® 1.4 EMI Regulations and Certifications Personal Computer Original Equipment Manufacturers (PC OEMs) ensure EMC compliance by meeting EMI regulatory requirements. PC designers must ensure that their computer systems do not exceed the emission limit standards set by applicable regulatory agencies.
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® System clock as a result of SSC 1/fm fnom time (1-δ)fnom Figure 1. Spread Spectrum Modulation Profile ∆ non-SCC SCC (1-δ)fnom fnom ssc.vsd Figure 2. Impact of Spread Spectrum Clocking on Radiated Emissions Radiated emissions are typically confined in a narrow band centered around clock frequency harmonics. By uniformly distributing the radiation over a band of a few MHz, regulatory measurement levels will be reduced. 2.
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® H-field caused by Iclk CLK - clock trace CLK' - clock bar trace Iclk Iclk' H-field caused by Iclk' Figure 3. Cancellation of H-fields Through Inverse Currents Differential clocking can also reduce the amount of noise coupled to other traces, which improves signal quality and reduces EMI.
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® frequency signals. Designers will have to experimentally investigate the behavior of a particular heatsink to determine its EMC performance. Grounding of the heatsink through the Intel processor package is not possible with the current package implementation but may be an option at some time in the future. As such, OEMs must design their own heatsink grounding solution.
Intel® Pentium® 4 Processor in the 423-pin package EMI Guideline ® Figure 4 Prototype Ground Frame 2.6 EMI Test Capabilities FCC regulations in the United States specify the maximum test frequency for products with clocks in excess of 1GHz is 5 times the highest clock frequency or 40 GHz, which ever is lower. Pentium® 4 processors are expected to initially be available at 1.4 GHz and 1.5 GHz, which means the maximum frequency which must be scanned is 7.5 GHz.
UNITED STATES, Intel Corporation 2200 Mission College Blvd., P.O. Box 58119, Santa Clara, CA 95052-8119 Tel: +1 408 765-8080 JAPAN, Intel Japan K.K. 5-6 Tokodai, Tsukuba-shi, Ibaraki-ken 300-26 Tel: + 81-29847-8522 FRANCE, Intel Corporation S.A.R.L. 1, Quai de Grenelle, 75015 Paris Tel: +33 1-45717171 UNITED KINGDOM, Intel Corporation (U.K.) Ltd.
