Question

Have you ever done this kind of BGA via window design example

Answer 1

The following is an example analysis of BGA via window design:
Design goal: Design a high-speed digital circuit board that requires high transmission rate, high reliability and good heat dissipation performance.
1. Stacked design: This circuit board adopts an 8-layer stacked design, of which the top and bottom layers are signal layers, and the middle 6 layers are power and ground layers. Such a design can provide sufficient signal transmission paths and power supplies while achieving good grounding effects.
2. BGA device placement: A BGA device is placed on the top layer, and its connectors are distributed around the device. Such a layout can ensure signal transmission quality and stability.
3. Via window design: A via window is opened between the top and bottom layers to connect the signal layers of the top and bottom layers. The size and position of the via window need to be designed according to the size and position of the connector to ensure signal transmission quality and stability.
4. Signal wiring: Route the wiring between the top layer and the bottom layer, and connect the top and bottom signal layers through the via window. The length and width of the traces need to be designed according to the frequency and current of the signal to ensure signal transmission quality and stability.
5. Power supply and grounding design: Some power supply and grounding holes are designed in the power supply and grounding layers to provide stable power supply and grounding effects for the circuit board. At the same time, by rationally arranging the location and number of power supply and ground holes, interference and noise between the power supply and ground layers can be reduced.
6. Heat dissipation design: A heat sink is designed under the BGA device to dissipate the heat of the device. The material and shape of the heat sink need to be designed according to the heat generation of the device and the ambient temperature to ensure stable operation of the circuit board.
Through the above design, the circuit board can achieve high-speed signal transmission, high reliability and good heat dissipation performance. At the same time, due to the compact structure, miniaturization and lightweight characteristics of the BGA via window design, it can meet the growing needs of modern electronic product design.

Answer 2

Yes, I have experience in BGA via window design. BGA (Ball Grid Array) is an integrated circuit packaging technology in which the pins are arranged on the bottom of the package in the form of a ball array grid through one or more solder balls. During the BGA routing process, it is usually necessary to use copper embedded holes (also called vias) for layer-by-layer connections.

For BGA via window design, there are several key aspects to consider:

BGA pinout and wiring: BGA pin density is high and wiring space is limited. Therefore, pin layout and wiring traces need to be properly arranged to ensure sufficient spacing and appropriate layering.

Via window design: In the PCB layer below the BGA pins, a via window needs to be created by laying barrier holes or leaving holes. Through these windows, the pins of the device can be connected to the contacts of the BGA.

Via window design size and position: The size and position of the via window need to accurately match the package specifications of the BGA pins. Typically, this requires reference to the BGA pin package specification and the design requirements provided by the PCB manufacturer.

Stackup design: Through proper stackup design, ensure that the PCB layers above and below the BGA pins have sufficient signal layers and ground layers to ensure signal integrity and power supply stability.

Rule checking and simulation: Use PCB design tools for rule checking and simulation to ensure that the layout and connections of the BGA via window do not cause signal integrity and impedance control issues.

In summary, BGA via window design requires precise planning and attention to detail to ensure good routing and reliable connections. Before executing this design, it is recommended to work with the PCB manufacturer and BGA packaging supplier and ensure that the relevant design specifications and requirements are fully understood.