LGA (Land Grid Array) components are surface mount technologies commonly used in the manufacture of electronic products. In contrast to other surface-mount components, the pins of LGA components are arranged at the bottom of the components through pads, rather than being inserted into the board from the side through pins. The welding of LGA components requires the following steps:
1. Preparations: Prepare LGA components, PCB boards, pads, and welding equipment (such as heat guns and reflow furnaces) to be welded.
2. Layout pad: According to the size and pin layout of the LGA components, arrange the corresponding pad on the PCB board to ensure that the position and size of each pad match the pin of the LGA components.
3. Place the LGA component: Gently place the LGA component on the PCB board, ensuring that it is aligned with the pad.
4. Heat the pad: Use heat gun or reflow furnace and other equipment to preheat the pad and make it reach the appropriate temperature.
5. Tinning: Apply an appropriate amount of solder to the pad, and let it melt and form a smooth tin coating on the pad surface.
6. Welding LGA components: gently press the LGA components on the pad to make full contact with the pad, and wait for the solder to cool and solidify.
7. Post-welding treatment: As required, the LGA components after welding are cleaned, tested and repaired to ensure their quality and stability.
It should be noted that in the welding process of LGA components, the heating temperature and time should be controlled to avoid overheating or undercooling leading to poor welding or component damage. At the same time, appropriate solder materials and welding processes should be selected to meet the needs of different application scenarios.
Manual welding is not recommended for the LGA package, and the reasons and treatment methods are as follows: There is no ball at the bottom of the LGA package, the important reason is to make the device as close as possible to the circuit board after welding, so as to dissipate heat through the circuit board. Planting balls at the bottom may cause heat.
(Otherwise, the manufacturer can directly make BGA) Because of multiple pads at the bottom, it is recommended to open the steel mesh solder paste and reflow welding treatment; Since most LGA packaged devices have a humidity sensitivity level of about level 3, they need to dry at 125 degrees for 48 hours after unpacking, or 150 degrees for 24 hours, so advanced drying is also required before welding. Otherwise, the circuit may be affected. The full name of LGA is LandGridArray, which literally translates to raster array packaging, corresponding to Intel's previous packaging technology Socket478, which is also known as SocketT. It is said to be a \"leapfrog technological revolution\
The LGA775, as the name suggests, has 775 contacts. Because the pin has become a contact, the processor using the LGA775 interface is also different from the current product in the installation method, it can not use the pin to fix the contact, but needs a mounting buckle to fix, so that the CPU can correctly press on the flexible tentacles exposed by the Socket, the principle is just like BGA package. But BGA is welded with tin, and LGA can be unlocked at any time to replace the chip.