1. From signal integrity to copper roughness and laminate design, you can use the following PCB design techniques:
2. Insertion loss and attenuation are crucial to designers, especially at very high speeds. For lower clock frequencies, designers can manage by slowing down the rising and falling edges. However, those working in the gigabyte realm must be particularly attentive to attenuation and loss. I learned a valuable lesson at PCB West on this topic. Many excellent materials can mitigate the effects of loss, such as I-speed materials. While I didn’t use those exact materials, I utilized others with similar loss characteristics, so I understand the advantages they offer.
3. In this context, the design community has received encouraging news. Current designs being manufactured usually incorporate pre-emphasis and equalization into the driver and receiver stages. Consequently, even with increasing speeds, the need for high-speed materials is diminished. You can acquire an IC that addresses loss by altering the waveform shape before or at the receiving end. This development is beneficial for the design community. It doesn’t eliminate the necessity for high-speed materials, but it reduces the demand significantly. When operating at 10 gigabytes, designers will require both equalization and/or pre-emphasis, along with low-loss PCB materials.
4. Individuals in the automotive and Internet of Things sectors typically prefer using very low-layer circuit boards, if possible. This is crucial because a low layer count translates to reduced costs. The challenge lies in designing 1, 2, and 4-layer circuit boards while maintaining high-quality signal integrity and managing EMI. This task is not always straightforward. Even with a single-layer circuit board, there are methods to control impedance and contain fields, but it typically necessitates comprehensive efforts. Each trace must have a return path akin to a high-speed board with elevated performance standards.
5. The critical element is maintaining close spacing between the wiring trace and the ground plane or ground wiring. As our colleague Dan Beeker always emphasizes, “Everything revolves around space.” This mindset is crucial for the IoT, automotive, and home appliance industries. Furthermore, as IC sizes decrease, they encounter the fine line issues prevalent in numerous other sectors. This affects everyone, necessitating consideration of the ramifications.
6. Thin lines are not mandatory for lower levels as long as the density remains low; standard line widths and copper weights can be used without issues. However, designers must grasp the concept of designing transmission lines. They must recognize that every signal from these devices operates swiftly. IC rise times are accelerating. It’s not merely about clock frequency but also about the rise and fall times of energy within the transmission line.
7. In average circuits, the power output maintains a relatively fixed voltage (e.g., 3.3V), leading many to assume they are dealing with DC energy, which isn’t the case. The current associated with the magnetic field is often of very high frequency, making powering the IC driving the transmission line a high-frequency event.
8. It’s rare to deal with real low-frequency currents, necessitating thicker aircraft. An oversight some make is assuming that power transmission mainly involves low frequencies; in reality, it’s mostly at very high frequencies. This energy frequency must align with the IC output’s switching speed. The power bus must encompass all harmonic frequencies in the square wave, from clock to 0.5 divided by the rise time, to the IC’s output driver. Consequently, the skin effect predominates during power supply.
9. When dealing with IC output edge rates under 500 picoseconds, frequencies of one, two, and three gigahertz come into play. Regarding copper’s current-carrying capacity, the skin effect becomes the dominant factor. In this realm, one ounce of copper isn’t superior to half an ounce. Once a specific frequency threshold is surpassed, the entire copper thickness isn’t utilized.
10. Some mistakenly believe they require a two-ounce copper plane. The key is evaluating current at high frequencies, calculating the skin effect, and determining the necessary copper thickness. In many instances, even a quarter ounce of copper suffices. Often, an ounce or two ounces of copper on a flat surface is unnecessary.
11. Unfortunately, copper roughness does impact performance. Analyzing problems often focuses on voltage and current, overlooking field-related issues. While the skin effect is a field-related concern, copper’s roughness complicates establishing a uniform current due to the magnetic field. As the current is field-induced, rougher copper impedes the flow, leading to greater losses.
12. At high frequencies, skin effect losses necessitate thin copper on the PCB. Manufacturing low and very thin ED copper takes longer, thus increasing costs. To achieve desired insertion loss in PCB transmission lines, thin copper becomes almost obligatory.
13. Energy within the circuit resides in the field. To ensure our circuit boards meet requirements and pass EMI tests, understanding the field’s presence on the PC board is essential. Stacks must be designed to contain fields, preventing expansion that could lead to interference or EMI issues. As Dan Beeker often remarks, “Everything revolves around space.” Designers must focus on containing fields, which entails proper circuit board stacking, partitioning, routing, layer changes, and so forth.
14. Ralph Morrison’s recent book, “Fast Circuit Boards/Energy Management,” is a vital resource for designers, providing insights into energy management in circuits to control interference, EMI, and signal integrity problems.
15. I encourage students to understand manufacturers’ circuit boards. If you require a 6-layer, 8-layer, or 10-layer board, familiarize yourself with the manufacturer’s preferred configurations. Understand the dielectric and copper weight. Design around these specifications for optimal outcomes. Communicate clearly with manufacturers about your board’s layers, facilitating better throughput. Our past experiences have shown that manufacturers can achieve up to 90% throughput on 12-layer, 14-layer, and 16-layer boards with stringent impedance control.
2. Insertion loss and attenuation are crucial to designers, especially at very high speeds. For lower clock frequencies, designers can manage by slowing down the rising and falling edges. However, those working in the gigabyte realm must be particularly attentive to attenuation and loss. I learned a valuable lesson at PCB West on this topic. Many excellent materials can mitigate the effects of loss, such as I-speed materials. While I didn’t use those exact materials, I utilized others with similar loss characteristics, so I understand the advantages they offer.
3. In this context, the design community has received encouraging news. Current designs being manufactured usually incorporate pre-emphasis and equalization into the driver and receiver stages. Consequently, even with increasing speeds, the need for high-speed materials is diminished. You can acquire an IC that addresses loss by altering the waveform shape before or at the receiving end. This development is beneficial for the design community. It doesn’t eliminate the necessity for high-speed materials, but it reduces the demand significantly. When operating at 10 gigabytes, designers will require both equalization and/or pre-emphasis, along with low-loss PCB materials.
4. Individuals in the automotive and Internet of Things sectors typically prefer using very low-layer circuit boards, if possible. This is crucial because a low layer count translates to reduced costs. The challenge lies in designing 1, 2, and 4-layer circuit boards while maintaining high-quality signal integrity and managing EMI. This task is not always straightforward. Even with a single-layer circuit board, there are methods to control impedance and contain fields, but it typically necessitates comprehensive efforts. Each trace must have a return path akin to a high-speed board with elevated performance standards.
5. The critical element is maintaining close spacing between the wiring trace and the ground plane or ground wiring. As our colleague Dan Beeker always emphasizes, “Everything revolves around space.” This mindset is crucial for the IoT, automotive, and home appliance industries. Furthermore, as IC sizes decrease, they encounter the fine line issues prevalent in numerous other sectors. This affects everyone, necessitating consideration of the ramifications.
6. Thin lines are not mandatory for lower levels as long as the density remains low; standard line widths and copper weights can be used without issues. However, designers must grasp the concept of designing transmission lines. They must recognize that every signal from these devices operates swiftly. IC rise times are accelerating. It’s not merely about clock frequency but also about the rise and fall times of energy within the transmission line.
7. In average circuits, the power output maintains a relatively fixed voltage (e.g., 3.3V), leading many to assume they are dealing with DC energy, which isn’t the case. The current associated with the magnetic field is often of very high frequency, making powering the IC driving the transmission line a high-frequency event.
8. It’s rare to deal with real low-frequency currents, necessitating thicker aircraft. An oversight some make is assuming that power transmission mainly involves low frequencies; in reality, it’s mostly at very high frequencies. This energy frequency must align with the IC output’s switching speed. The power bus must encompass all harmonic frequencies in the square wave, from clock to 0.5 divided by the rise time, to the IC’s output driver. Consequently, the skin effect predominates during power supply.
9. When dealing with IC output edge rates under 500 picoseconds, frequencies of one, two, and three gigahertz come into play. Regarding copper’s current-carrying capacity, the skin effect becomes the dominant factor. In this realm, one ounce of copper isn’t superior to half an ounce. Once a specific frequency threshold is surpassed, the entire copper thickness isn’t utilized.
10. Some mistakenly believe they require a two-ounce copper plane. The key is evaluating current at high frequencies, calculating the skin effect, and determining the necessary copper thickness. In many instances, even a quarter ounce of copper suffices. Often, an ounce or two ounces of copper on a flat surface is unnecessary.
11. Unfortunately, copper roughness does impact performance. Analyzing problems often focuses on voltage and current, overlooking field-related issues. While the skin effect is a field-related concern, copper’s roughness complicates establishing a uniform current due to the magnetic field. As the current is field-induced, rougher copper impedes the flow, leading to greater losses.
12. At high frequencies, skin effect losses necessitate thin copper on the PCB. Manufacturing low and very thin ED copper takes longer, thus increasing costs. To achieve desired insertion loss in PCB transmission lines, thin copper becomes almost obligatory.
13. Energy within the circuit resides in the field. To ensure our circuit boards meet requirements and pass EMI tests, understanding the field’s presence on the PC board is essential. Stacks must be designed to contain fields, preventing expansion that could lead to interference or EMI issues. As Dan Beeker often remarks, “Everything revolves around space.” Designers must focus on containing fields, which entails proper circuit board stacking, partitioning, routing, layer changes, and so forth.
14. Ralph Morrison’s recent book, “Fast Circuit Boards/Energy Management,” is a vital resource for designers, providing insights into energy management in circuits to control interference, EMI, and signal integrity problems.
15. I encourage students to understand manufacturers’ circuit boards. If you require a 6-layer, 8-layer, or 10-layer board, familiarize yourself with the manufacturer’s preferred configurations. Understand the dielectric and copper weight. Design around these specifications for optimal outcomes. Communicate clearly with manufacturers about your board’s layers, facilitating better throughput. Our past experiences have shown that manufacturers can achieve up to 90% throughput on 12-layer, 14-layer, and 16-layer boards with stringent impedance control.
