Board-to-board connector manufacturers tell you how to choose connectors. There are many types of connectors. Common types include communication interface terminals, wiring terminals, wire-to-board connectors, and board-to-board connectors. Each category can be subdivided into several categories, such as: board-to-board connectors include pin headers and females headers, board-to-board connectors, etc.; wire-to-board connectors include FPC connectors, IDC sockets, and simple horn sockets(ejector box headers).
So when choosing a connector, what aspects should we consider to choose a connector suitable for hardware use?
1. Pins and spacing
The number of pins and pin spacing are the basic basis for connector selection. The number of pins selected for the connector depends on the number of signals to be connected. For some patch connectors, the number of pins in the patch headers as shown below should not be too much. Because in the soldering process of the placement machine, due to the effect of high temperature, the connector plastic will be heated and deformed, and the middle part will bulge, resulting in false soldering of the pins. In the early development of our P800Flash programmer, this header and female header were used for board-to-board connection. As a result, the pins of the prototype header were soldered in large areas. After changing to 2 pin headers with halved pins, there was no false soldering.
Nowadays, electronic equipment is developing towards miniaturization and precision, and the pin pitch of the connector has also changed from 2.54mm to 1.27mm, and then to 0.5mm. The smaller the lead pitch, the higher the requirements for the production process. The pin spacing should be determined by the company's production technology level, do not blindly pursue small-pitch connectors.
2. Electrical performance
The electrical performance of the connector mainly includes: limiting current, contact resistance, insulation resistance and dielectric strength, etc. When connecting a high-power power supply, pay attention to the limit current of the connector; when transmitting high-frequency signals such as LVDS, PCIe, etc., pay attention to the contact resistance. The connector should have a low and constant contact resistance, generally tens of mΩ to hundreds of mΩ.
3. Environmental performance
The environmental performance of the connector mainly includes: resistance to temperature, humidity, salt spray, vibration, shock, etc. Choose according to specific application environment. If the application environment is relatively humid, the requirements for moisture resistance and salt spray resistance of the connector are high to prevent the metal contacts of the connector from being corroded. In the field of industrial control, the requirements for the anti-vibration and impact performance of the connector are high to prevent the connector from falling off during the vibration process.
4. Mechanical properties
The mechanical properties of the connector include insertion force, mechanical foolproof, etc. Mechanical foolproof is very important to the connector. Once plugged in reverse, it may cause irreversible damage to the circuit!
The insertion force is divided into insertion force and separation force. The relevant standards specify the maximum insertion force and minimum separation force. From the perspective of use, the insertion force should be small and the separation force should be large. Too little separation force will reduce the reliability of contact, but for connectors that often need to be plugged and unplugged, too much separation force will increase the difficulty of unplugging and reduce mechanical life.
In order to reduce the separation force of the connector and make it easier for users to plug and unplug the adapter board, we made many attempts, and finally found a beacon on the road of exploration, and finally chose the connector shown in the figure below, and modified the PCB and products. Shell structure.
Actual tests show that due to the unique directionality of the socket, this connector has obvious foolproof effects, small insertion force, moderate separation force, and good plug-in feel, which greatly improves the convenience of plug-in parts.
Connectors are used to connect two circuit boards or electronic devices to realize power or signal transmission. Through the connector, the circuit can be modularized, the assembly process of the electronic product can be simplified, and the product can be easily maintained and upgraded. For modular circuits, the selection of connectors plays a decisive role.