1. Currently, most hardware engineers rely solely on experience when designing PCB boards.
2. Throughout the debugging process, many crucial signal lines or chip pins are often buried within the middle layer of the PCB, making them inaccessible for observation using tools like oscilloscopes.
3. In cases where a product fails functional testing, engineers face a challenge in pinpointing the root cause due to this limitation.
4. To evaluate the EMC characteristics of a product, engineers typically resort to conducting measurements in a standard electromagnetic compatibility testing facility.
5. However, these measurements primarily focus on the product’s external radiation, rendering them insufficient for diagnosing underlying issues even in the event of failure.
6. Consequently, engineers resort to iterative empirical modifications to the PCB design followed by repeated testing—a costly and time-consuming process that inevitably delays time to market.
7. While there exist several high-speed PCB analysis and simulation tools, their utility is often hampered by limitations in device models.
8. Notably, many devices lack the necessary IBIS models essential for conducting signal integrity (SI) simulations, or the available models may prove inaccurate.
9. To simulate EMC issues effectively, engineers often require SPICE models; however, the majority of ASICs currently lack this capability.
10. Absence of SPICE models precludes the consideration of the device’s own radiation, which often surpasses that of the transmission line.
11. Furthermore, simulation tools frequently necessitate a trade-off between accuracy and computational time, with higher precision simulations requiring longer processing times, while faster tools sacrifice precision.
12. Consequently, utilizing these tools fails to entirely mitigate the challenges posed by mutual interference in high-speed PCB board design.
We understand that in a multi-layer PCB board, the return path of high-frequency signals should ideally be on the reference ground plane (power layer or ground layer) adjacent to the signal line layer. However, in reality, the ground layer or power supply layer may feature divisions and hollowing out, thus altering the return path. This can lead to a larger return area, resulting in electromagnetic radiation and ground bounce noise. Engineers, if able to comprehend the current paths, can circumvent large return paths and effectively manage electromagnetic radiation. Yet, the determination of the signal return path is influenced by numerous factors including signal line wiring, PCB power supply and ground distribution structure, power supply point, decoupling capacitor, and device placement position and quantity. Hence, theoretically determining the return path of a complex system poses significant challenges. Consequently, eliminating radiated noise problems during the design phase is crucial. While oscilloscopes aid in addressing signal integrity issues by visualizing signal waveforms, is there a device capable of discerning the “pattern” of radiation and reflow on the board?
Among various electromagnetic radiation measurement methods, a near-field scanning measurement method addresses this concern. It operates on the principle that electromagnetic radiation originates from high-frequency current loops on the Device Under Test (DUT). For instance, the electromagnetic radiation scanning system, Emscan, developed by the Canadian company EMSCAN, operates on this principle. It utilizes H-field array probes (32×40=1280 probes) to detect current on the DUT. During measurement, the DUT is positioned directly on the scanning top of the device. These probes detect changes in electromagnetic fields due to alterations in high-frequency currents, providing a visual image of the spatial distribution of RF currents on the PCB. The Emscan electromagnetic compatibility scanning system finds wide application in industrial sectors such as communications, automobiles, office appliances, and consumer electronics. Through the current density map provided by the system, engineers can identify areas with EMI problems before conducting electromagnetic compatibility standard tests and take appropriate action.
The principle behind Emscan’s measurement primarily operates in the active near-field region (r
2. Throughout the debugging process, many crucial signal lines or chip pins are often buried within the middle layer of the PCB, making them inaccessible for observation using tools like oscilloscopes.
3. In cases where a product fails functional testing, engineers face a challenge in pinpointing the root cause due to this limitation.
4. To evaluate the EMC characteristics of a product, engineers typically resort to conducting measurements in a standard electromagnetic compatibility testing facility.
5. However, these measurements primarily focus on the product’s external radiation, rendering them insufficient for diagnosing underlying issues even in the event of failure.
6. Consequently, engineers resort to iterative empirical modifications to the PCB design followed by repeated testing—a costly and time-consuming process that inevitably delays time to market.
7. While there exist several high-speed PCB analysis and simulation tools, their utility is often hampered by limitations in device models.
8. Notably, many devices lack the necessary IBIS models essential for conducting signal integrity (SI) simulations, or the available models may prove inaccurate.
9. To simulate EMC issues effectively, engineers often require SPICE models; however, the majority of ASICs currently lack this capability.
10. Absence of SPICE models precludes the consideration of the device’s own radiation, which often surpasses that of the transmission line.
11. Furthermore, simulation tools frequently necessitate a trade-off between accuracy and computational time, with higher precision simulations requiring longer processing times, while faster tools sacrifice precision.
12. Consequently, utilizing these tools fails to entirely mitigate the challenges posed by mutual interference in high-speed PCB board design.
We understand that in a multi-layer PCB board, the return path of high-frequency signals should ideally be on the reference ground plane (power layer or ground layer) adjacent to the signal line layer. However, in reality, the ground layer or power supply layer may feature divisions and hollowing out, thus altering the return path. This can lead to a larger return area, resulting in electromagnetic radiation and ground bounce noise. Engineers, if able to comprehend the current paths, can circumvent large return paths and effectively manage electromagnetic radiation. Yet, the determination of the signal return path is influenced by numerous factors including signal line wiring, PCB power supply and ground distribution structure, power supply point, decoupling capacitor, and device placement position and quantity. Hence, theoretically determining the return path of a complex system poses significant challenges. Consequently, eliminating radiated noise problems during the design phase is crucial. While oscilloscopes aid in addressing signal integrity issues by visualizing signal waveforms, is there a device capable of discerning the “pattern” of radiation and reflow on the board?
Among various electromagnetic radiation measurement methods, a near-field scanning measurement method addresses this concern. It operates on the principle that electromagnetic radiation originates from high-frequency current loops on the Device Under Test (DUT). For instance, the electromagnetic radiation scanning system, Emscan, developed by the Canadian company EMSCAN, operates on this principle. It utilizes H-field array probes (32×40=1280 probes) to detect current on the DUT. During measurement, the DUT is positioned directly on the scanning top of the device. These probes detect changes in electromagnetic fields due to alterations in high-frequency currents, providing a visual image of the spatial distribution of RF currents on the PCB. The Emscan electromagnetic compatibility scanning system finds wide application in industrial sectors such as communications, automobiles, office appliances, and consumer electronics. Through the current density map provided by the system, engineers can identify areas with EMI problems before conducting electromagnetic compatibility standard tests and take appropriate action.
The principle behind Emscan’s measurement primarily operates in the active near-field region (r
