PCB Blog - PCB Design Factors You Need to Pay Attention to

For the article on PCB board technology, the challenges faced by PCB board design engineers in recent times, this article will explain the challenges faced by PCB board design, and what factors should be considered when a PCB board designer is a PCB board design tool. Here are a few factors that PCB board designers must consider and influence their decision:

1. Product Features
1.1 Essential functions covering essential requirements, including:
1) Interaction between schematic and PCB board layout
2) Routing functions such as automatic fan-out routing, push-pull, and routing capabilities based on design rule constraints
3) DRC checker
1.2 The ability to upgrade product functionality as the company engages in a more complex design
1) HDI (High-Density Interconnect) interface
2) Flexible design
3) Embed passive components
4) Radio Frequency (RF) Design
5) Automatic script generation
6) Topological layout and routing
7) Manufacturability (DFF), Testability (DFT), Manufacturability (DFM), etc.
1.3 Additional products can perform analog simulation, digital simulation, analog-digital mixed-signal simulation, high-speed signal simulation, and RF simulation
1.4 Have a central component library that is easy to create and manage

2. A good partner who is technically in the leadership of the industry and has devoted more effort than other manufacturers, can help you design products with efficacy and technology in a short period of time

3. Price should be a secondary consideration among the above factors, more attention should be paid to ROI!
There are many factors to consider in PCB board evaluation. The type of development tools a designer is looking for depends on the complexity of the design work they are doing. As systems tend to become more complex, control of physical routing and placement of electrical components has grown so extensive that constraints must be placed on critical paths in the design process. However, too many design constraints limit the flexibility of the design. Designers must have a good understanding of their designs and their rules so they know when to use those rules. This design definition is tightly integrated with constraint editing. In constraint editing, designers can define both physical and electrical constraints. Electrical constraints will drive the simulator for pre-placement and post-placement analysis for network verification. Taking a closer look at the design definition, it is also linked to FPGA/PCB board integration. The purpose of FPGA/PCB board integration is to provide bidirectional integration, data management, and the ability to perform co-design between the FPGA and the PCB board. The same constraint rules for physical implementation are entered during the layout phase as during the design definition. This reduces the chance of errors going from file to layout. Pipe exchange, logic gate exchange, and even input and output interface group (IO_Bank) exchange all need to return to the design definition stage for updating, so the design of each link is synchronized.

2.1 HDI
The increase in semiconductor complexity and the total number of logic gates have required integrated circuits with more pins and finer pin pitches. It is common to design more than 2000 pins on a BGA device with a 1mm pitch, let alone 296 pins on a device with a 0.65mm pitch. Faster rise times and Signal Integrity (SI) requirements require a higher number of power and ground pins, which require more layers in a multilayer board, thereby driving a high demand for microvias. The need for density interconnects (HDI) technology. HDI is an interconnect technology that is being developed in response to the above needs. Micro vias and ultra-thin dielectrics, thinner traces, and smaller line spacing are key features of HDI technology.

2.2 RF Design
For RF design, RF circuits should be designed directly into the system schematic and system board layout, rather than a separate environment for subsequent conversions. All of the simulation, tuning and optimization capabilities that the RF simulation environment provides are still required, but the simulation environment accepts more raw data than the "real" design. As a result, the differences between the data models and the resulting problems of design transitions will disappear. First, designers can interact directly between system design and RF simulation; second, if designers are working on a large-scale or fairly complex RF design, they may want to distribute circuit simulation tasks to multiple computing platforms running in parallel, or They wanted to reduce simulation time by sending each circuit in a multi-block design to its own simulator.

2.3 Advanced Packaging
The increasing functional complexity of modern products requires a corresponding increase in the number of passive components, mainly reflected in the increase in the number of decoupling capacitors and termination resistors in low-power, high-frequency applications. While the packaging of passive surface mount devices has shrunk considerably over the years, the results are still the same when trying to achieve the ultimate density. Printed component technology has enabled the transition from multi-chip assemblies (MCMs) and hybrid assemblies to today's SiP and PCB boards that are directly embedded as passive components. The assembly technology is used in the transformation process. For example, the inclusion of a layer of resistive material in a layered structure and the use of series termination resistors directly under the micro ball grid array (BGA) package have greatly improved circuit performance. Embedded passive components can now be designed with high precision, eliminating the need for additional processing steps for laser-cleaned welds. There is also a movement towards increased integration directly within the substrate in wireless components.

2.4 Rigid-flex PCB
In order to design a rigid-flex PCB board, all factors that affect the assembly process must be considered. Designers cannot design a rigid-flex PCB as simple as designing a rigid PCB, as if the rigid-flex PCB were just another rigid PCB. They must manage the bend area of the design to ensure that design points will not cause conductor breakage and stripping due to stress on the bending surface. There are still many mechanical factors to consider, such as bend radius, dielectric thickness and type, sheet metal weight, copper plating, overall circuit thickness, number of layers, and number of bends. Understand the rigid-flex design and decide if your product allows you to create a rigid-flex design.

2.5 Signal Integrity Planning
In recent years, new technologies related to parallel bus structures and differential pair structures for serial-to-parallel conversion or serial interconnection have been advancing. Types of typical design problems encountered for a parallel bus and serial-to-parallel conversion design. The limitations of parallel bus design are changes in system timing, such as clock skew and propagation delays. Designing for timing constraints remains difficult due to clock skew across the bus width. Increasing the clock rate will only make the problem worse. On the other hand, the differential pair structure uses an exchangeable point-to-point connection at the hardware level for serial communication. Typically, it transfers data over a unidirectional serial "lane" that can be stacked in 1-, 2-, 4-, 8-, 16-, and 32-width configurations. Each channel carries one byte of data, so the bus can handle data widths from 8 to 256 bytes, and data integrity can be maintained through the use of some form of the error detection technique. However, other design issues arise due to the high data rates. Clock recovery at high frequencies becomes a burden on the system, as the clock needs to quickly lock to the incoming data stream and reduce all cycle-to-cycle jitter in order to improve the circuit's anti-jitter performance. Power supply noise also creates additional problems for designers. This type of noise increases the potential for severe jitter, which makes eye-opening more difficult. Another challenge is to reduce common-mode noise and address issues caused by loss effects from IC packages, PCB boards, cables, and connectors.

2.6 Utility of Design Kits
Design kits such as USB, DDR/DDR2, PCI-X, PCI-Express, and RocketIO will undoubtedly be of great help to designers entering new technologies. The Design Kit gives an overview of the technology, detailed descriptions, and difficulties that designers will face, followed by simulation and how to create routing constraints. It provides descriptive documentation along with the program, which provides designers with an opportunity to master advanced new technologies. It may seem easy to get a PCB board tool that can handle layout; but getting a tool that not only satisfies layout but also solves your pressing needs is critical.