The use of SIM card holder connectors has rapidly developed in the electronics industry. As the demand for electronic devices expands, SIM card holder connectors have become indispensable accessories. They find applications in mobile phones, computers, and other devices, making it crucial to pay attention to their performance indicators. Below, Hanbo Electronic, an LCSC supplier, explains the circuit principles behind SIM card holder connectors.
Whether it is a large card or a small card, the SIM card holder has several basic SIM card interface terminals: card clock (SIMCLK), card reset (SIMRST), card power (SIMVCC), ground (SIMGND) and card data (SIM/O or SIMDAT). The card holder provides an interface for the mobile phone to communicate with the SIM card. The spring contact within the card holder touches the SIM card, so if the spring becomes deformed, it can cause SIM card issues such as “check card” or “insert card” errors. There are two types of SIM card power supplies: 3V and 5V. Early mobile phone SIM cards typically used 5V, while most modern SIM cards operate at 3V. The SIM card clock operates at 3.25 MHz, and the I/O terminal serves as the data input and output port for the SIM card. When the SIM card circuit is active, the SIM card clock and card data ports emit a pulse signal.
The power supply terminals SIMVCC and SIMGND are essential for the card circuit to function properly. Early mobile phones used a card switch to detect whether the card was inserted into the CPU. The mechanical action of the card switch often led to damage. Newer mobile phones have eliminated this switch, instead using data collection to determine card insertion status. This approach reduces issues caused by improperly positioned or damaged card switches. The SIM card typically receives power from the power module, with the CPU card interface signal controlling the power supply.
Card Detection Circuit
A resistor pulls the card detection pin of the SIM card up to the power supply. When you do not insert a card, the pin stays at a high voltage level.
The structural principle of the SIM card holder involves using a spring design for self-ejection. The design complies with national standards for card holder specifications. During manufacturing, we apply a layer of wear-resistant gold to the surface of the SIM card holder. This coating improves durability and extends the holder’s service life. Hanbo’s SIM card holder delivers excellent card ejection performance, high weldability, and flatness. We design the contact area to ensure reliable performance and prevent issues of poor contact. Buyers can use it with confidence.
LCSC Electronics is the authorized distributor for Hanbo, offering an extensive inventory of over 560,000 in-stock SKUs from more than 2,600 manufacturers. Explore and select Hanbo’s SIM card holder connectors and other products on LCSC.
