ALLEGRO Pad Preparation Steps
Padstack: This is a group of PADs. It also includes Regular Pad / Thermal relief / AnTI pad / SolderMask / PasteMask. Below we understand one by one: 1. Regular Pad: regular pad (positive film). 2. AnTI pad: An isolation ring around the hole used to connect the isolation hole to the inner layer. If the hole does not require electrical connections in the inner layer, the AnTI pad is required to be isolated. The inner diameter is of course greater than that of the hole. path. Detailed explanation of ALLEGRO pad production process Padstack: It's a group of PADs. It also includes Regular Pad / Thermal relief / AnTI pad / SolderMask / PasteMask Here we understand one by one: 1. Regular Pad: Regular pad (positive film). 2. Anti pad: The isolation ring around the hole used to connect the isolation hole and the inner layer. If the hole does not need electrical connection in the inner layer, Anti pad is needed to isolate it. The inner diameter of the pad is certainly larger than that of the hole. path. 3. Thermal relief: Hot air pad (possibly present in both positive and negative plates): If the copper plate requires a wire connection at this layer, then the above isolation ring will be modified to be spoke-like to connect the internal copper connection of the isolation ring. To the outside of the isolation ring, this is what is known as thermal relief. Of course, we can completely remove the isolation ring, and make the isolation ring inside and outside one. But why not do it because it is easy to make the pad when welding Cold welding, because this greatly increases the thermal conductivity of the pad. So in order to ensure the electrical connection of the pad, but also to prevent such a high thermal conductivity, we will be as "spoke" like. For the via, it is a special case Because the vias do not need to be soldered, there is no high thermal conductivity above. So we simply remove the anti pad because of this conductivity. Of course if you have to use spokes. You can't do it, but for those Need to add holes to balance PCB board heat dissipation design, using this fully connected via hole is even better! 4. SolderMask Solder Pad (Green Layer): This is the non-wiring layer of the circuit board. It is used to make the screen blanking board and apply solder resist to the areas that do not need soldering. (>Regular Pad) 5. PasteMask Steel Plate Pad: This is a non-wiring layer. This layer is used to make the steel film (sheet), and the hole in the steel film corresponds to the solder joint of the SMD device on the circuit board. (This layer has the same size as the actual SMD pad) Further explanation: Regular pad It is mainly connected with all positive films such as top layer, bottom layer, and internal layer (including wiring and copper plating). Generally used in the top, bottom, and signal layers. It is mainly connected with negative film and isolation insulation. Generally used in the internal electrical layer such as VCC or GND. However, we also set the thermal relief/anti pad parameters in the begin layer and end layer. This is because the begin layer and the end layer may also be used as internal electrical layers, and they may also be negative. Distribution Transformer,2500Kva Transformer,High Quality 1250Kva Transformer,High Quality 800Kva Transformer Hangzhou Qiantang River Electric Group Co., Ltd.(QRE) , https://www.qretransformer.com
Thermal relief/anti pad
In summary, that is, for a fixed pad connection, if your layer is positive, then connect to this pad through the regular pad you set, thermal relief, anti pad ( The isolation plate) has no effect on this layer. If this layer is negative, it is connected and isolated by thermal relief and anti pad. The regular pad has no effect on this layer. Of course, a pad can also be connected to the network with a positive pad of the regular pad and the top layer. At the same time, a thermal relief is used to connect the negative layer of the internal layer of the GND with the network.