AN2321 Freescale Semiconductor / Motorola, AN2321 Datasheet
AN2321
Related parts for AN2321
AN2321 Summary of contents
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... Freescale Semiconductor, Inc. Application Note AN2321/D Rev. 0, 8/2002 Designing for Board Level Electromagnetic Compatibility By T.C. Lun Applications Engineering Microcontroller Division Hong Kong This application note discusses board level electromagnetic compatibility (EMC), from component selection, circuit design, to printed circuit board layout. The text is divided into the following parts: • ...
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... Freescale Semiconductor, Inc. AN2321/D Elements of the A simple EMI model consists of three elements: Electromagnetic • Environment • • This is shown graphically in EMI source EMI sources include microprocessors, microcontrollers, electrostatic discharges, transmitters, transient power components such as electromechanical relays, switching power supplies, and lightning. Within a ...
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... For More Information On This Product, PART 1: AN OVERVIEW OF ELECTROMAGNETIC INTERFERENCE AND COMPATIBILITY 1. The radiated coupling path will be more efficient in the higher Product Circuit PCB Layout Prototype Definition Design Figure 2. Cost of EMC Measures Go to: www.freescale.com AN2321/D Figure 2). Functional and Mass Product Compliance Test Production Launch 3 ...
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... Freescale Semiconductor, Inc. AN2321/D PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES Component selection and circuit design are major factors that will affect board level EMC performance. Each type of electronic components has its own characteristics, and therefore requires careful design considerations. The following sections will discuss some common electronic components and circuit design techniques for reducing or suppressing EMI ...
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... PCBs with a large number of integrated circuits, fast switching circuits, and PSUs having long leads to the PCB. MOTOROLA Designing for Board Level Electromagnetic Compatibility For More Information On This Product, PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES Go to: www.freescale.com AN2321/D 5 ...
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... Freescale Semiconductor, Inc. AN2321/D Decoupling capacitors During active device switching, the high frequency switching noise created is distributed along the power supply lines. The main function of the decoupling capacitor is to provide a localized source of DC power for the active devices, thus reducing the switching noise propagating across the board and decoupling the noise to ground ...
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... PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES Table 1. Capacitor Self-Resonant Frequencies Through-hole (0.25 leads) 1.0 µ F 2.5 MHz 0.1 µ MHz 0.01 µ MHz 1000 pF 80 MHz 100 pF 250 MHz 10 pF 800 MHz Go to: www.freescale.com AN2321/D Surface mount (0805) 5 MHz 16 MHz 50 MHz 160 MHz 500 MHz 1.6 GHz 7 ...
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... Freescale Semiconductor, Inc. AN2321/D There are basically two types of inductors: open-loop and closed-loop. Their difference is in their magnetic field loop. In the open-loop design, the magnetic field passes through air to complete its field, while in the closed-loop design, the magnetic field flows through its core material to complete the magnetic circuit ...
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... For More Information On This Product, PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES Figure 6 can be used. LOW IMPEDANCE C POWER SUPPLY Z HI Figure 6. LC Filter Figure 7. AC Mains Filter Go to: www.freescale.com AN2321/D HIGH IMPEDANCE DIGITAL CIRCUIT ...
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... Freescale Semiconductor, Inc. AN2321/D In Figure filtering by its leakage inductance and differential mode filtering by its primary inductance. L1, C filter out noise between the supply lines. L1, C mode filtering network which reduces noise from ground loops and earth offset. For a 50 Ω terminating impedance, the EMI filter typically can fall-off at about 50dB/decade in differential mode and 40dB/decade in common mode ...
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... The switching SWITCH VCC D1 D2 GND Figure 9. DC Switch Transient Suppression Figure 9 is used to suppress the voltage transients D1 TXFR D2 Figure 10. Transformer DC Transient Suppression shows the typical transformer and rectifier configuration to: www.freescale.com AN2321/D RELAY ...
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... Freescale Semiconductor, Inc. AN2321/D In motor control applications, both brush and brushless motors will generate brush noise or commutator noise when the motor is running. Therefore, suppression diodes are necessary to reduce the noise. To improve the effectiveness of the suppression, the diodes should be placed as close as possible to the motor contacts. ...
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... For More Information On This Product, PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES Figure 11 shows the bypass and decoupling 78XX + 100 to INPUT 0.1 µ F 0.1 µ F 470 µ F Figure 11. Regulator Bypass and Decoupling Table 3 lists a summary of the termination methods. Go to: www.freescale.com AN2321/D + 100 to OUTPUT 470 µ ...
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... Freescale Semiconductor, Inc. AN2321/D Table 3. Summary of Termination Methods Termination Relative Delay Added Type Cost Series Low Parallel Low RC Medium Thevenin Medium Diode High Series/Source termination Figure 12 termination resistor, R source, Z load. R must be placed as close as possible to the source driver. The value the real part in the equation Ω ...
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... It is formed by the R1 is such that the maximum current cannot exceed the source driver L R2 330 -------------------- - × ----------------------- - × VCC = 330 + 220 Go to: www.freescale.com AN2321/D LOAD LOAD ...
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... Freescale Semiconductor, Inc. AN2321/D Diode termination Figure 16 termination, except that the resistors are replaced by diodes, which has a lower power consumption. The D1 and D2 configuration is used to limit overshoots of the reflected signal from the load. The diodes do not affect the line impedance, unlike the thevenin termination. Schottky and fast switching diodes are good choice to use for this type of termination ...
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... Motorola HC08 MCU). There are also limits for the minimum resistor impedance since the maximum pull-down current is MOTOROLA Designing for Board Level Electromagnetic Compatibility For More Information On This Product, PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES Go to: www.freescale.com AN2321/D 17 ...
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... Freescale Semiconductor, Inc. AN2321/D approximately 5mA source of the external capacitor necessary to ensure a minimum pull-up resistor value of 2k Ω diode to clamp the voltage of the reset pin is also recommended to prevent the voltage from exceeding the supply voltage and also to provide a faster discharge for the capacitor when the supply is removed ...
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... For More Information On This Product, PART 2: COMPONENT SELECTION AND CIRCUIT DESIGN TECHNIQUES 18. Q Figure 18. Crystal Equivalent Circuit for a particular crystal are specified in the crystal and C2 not only depends on the inverter 0 Go to: www.freescale.com AN2321 the shunt capacitance ...
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... Freescale Semiconductor, Inc. AN2321/D PART 3: PRINTED CIRCUIT BOARD LAYOUT TECHNIQUES In addition to component selection and circuit design, good printed circuit board (PCB) layout is an important factor in EMC performance. Since the PCB is an inherent part of the system, EMC enhancements by PCB layout does not add extra cost towards the finish product ...
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... Widen ground and power tracks to reduce the impedance of both power and ground lines. VCC GND GND VCC Digital circuit Unmetallized moats Figure 19. Separated Function Blocks shows a typical example of separating four different circuits using the Go to: www.freescale.com AN2321/D Analog circuit DC circuit Interface circuit 21 ...
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... Freescale Semiconductor, Inc. AN2321/D Decouple Local Localized decoupling can reduce noise propagating along the supply rail. The Supplies and ICs use of large bypass capacitors connected at supply entry to the PCB will help as a low frequency ripple filter and potential reservoir for sudden power demands ...
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... Designing for Board Level Electromagnetic Compatibility For More Information On This Product, PART 3: PRINTED CIRCUIT BOARD LAYOUT TECHNIQUES Guard trace Magnetic flux 3W Grounded at driver end Figure 21. Shunt and Guard Traces Go to: www.freescale.com AN2321 Critical Signal trace Guard trace Grounded at destination end ...
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... Freescale Semiconductor, Inc. AN2321/D Ground track double-layer (double sided) PCB, the ground grid/matrix arrangement is double-layer PCBs preferred for digital circuits because this arrangement can reduce ground impedance, ground loops, and signal return loops. As with the single-layer PCBs, the width of the ground and power tracks should be at least 1.5mm. ...
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... Ground plane layer PCB capacitor Power plane layer Non-critical signals layer Figure 23. Tracking Arrangement on Multi-Layer PCBs Star points Bypass capacitor Figure 24. Multiple Power Sources Go to: www.freescale.com AN2321/D Laminate Laminate Laminate Figure 24). This still helps to avoid +12V 7812 GND Voltage regulators GND ...
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... Freescale Semiconductor, Inc. AN2321/D Vias Vias or via holes are commonly used for multi-layer PCBs. On high speed signals, a via introduces 1 to 4nH of inductance and 0.3 to 0.8pF of capacitance to the track. Hence, vias should be kept to an absolute minimum when laying high speed signal tracks. If layer changes are unavoidable on high- speed parallel lines (e ...
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... MOTOROLA Designing for Board Level Electromagnetic Compatibility For More Information On This Product, PART 3: PRINTED CIRCUIT BOARD LAYOUT TECHNIQUES Figure 27). GND Critical signal return Re-routing the ground to reduce ground loop Figure 27. Ground Return Loops Go to: www.freescale.com AN2321/D loop 27 ...
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... Freescale Semiconductor, Inc. AN2321/D PCB Example 1 Figure 28 a washing machine. Add series termination resistors, and filter capacitor in the two lines of the power switch Change 90 ° traces to 45 ° and the 45 ° trace must be greater than 10 × the trace width All traces must be routed far ...
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... Add 0.01 µ F and 470 µ F capacitors at the 5V supply source (connect between 5V and GND) Enlarge 5V trace and connect all 5V as close as possible Go to: www.freescale.com AN2321/D Enlarge GND trace and connect all GND as close as possible Enlarge GND trace at the MCU VSS pins and add 0.01 µ F capacitors ...
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... Freescale Semiconductor, Inc. AN2321/D APPENDIX A: GLOSSARY OF TERMS Electromagnetic The capability of electrical and electronic systems, equipment, and devices to Compatibility operate in their intended electromagnetic environment within a defined margin (EMC) of safety, and at design levels or performance, without suffering or causing unacceptable degradation as a result of electromagnetic interference (ANSI C64 ...
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... When the amplitude of the RF field is sufficient, induced voltages and demodulated carriers can disrupt the operation of a device. MOTOROLA Designing for Board Level Electromagnetic Compatibility For More Information On This Product, APPENDIX B: IMMUNITY MEASUREMENT STANDARDS Go to: www.freescale.com AN2321/D 31 ...
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... Freescale Semiconductor, Inc. AN2321/D Performing the This test is usually the longest and most difficult to perform, requiring very radiated immunity test expensive capital equipment and considerable expertise. As with other immunity testing, pass/fail criteria must be defined by the manufacturer and a written test plan submitted to the test house. The EUT must be arranged for normal operation and in the most sensitive mode, while subjecting it to radiated fields ...
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... EUT. One solution is to use a remotely controlled EMI hardened closed circuit TV system. MOTOROLA Designing for Board Level Electromagnetic Compatibility For More Information On This Product, APPENDIX B: IMMUNITY MEASUREMENT STANDARDS Go to: www.freescale.com AN2321/D 33 ...
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... Freescale Semiconductor, Inc. AN2321/D Immunity to The purpose of this standard is to verify the EUT immunity against conducted Conducted RF RF disturbances in the frequency range 9kHz to 230MHz. The EUT is Disturbances: functioned and monitored in accordance with the prepared test plan while the IEC 1000-4 injected onto the leads. All cables of the EUT can act as receptors of radiated RF energy which can then appear on the cables as voltages Vrms ...
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... Freescale Semiconductor, Inc. NOTES MOTOROLA Designing for Board Level Electromagnetic Compatibility For More Information On This Product, Go to: www.freescale.com AN2321/D NOTES 35 ...
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... Motorola and the Stylized M Logo are registered in the U.S. Patent and Trademark Office. digital dna is a trademark of Motorola, Inc. All other product or service names are the property of their respective owners. Motorola, Inc Equal Opportunity/Affirmative Action Employer. © Motorola, Inc. 2002 AN2321/D Go to: www.freescale.com ...