SIM card (Subscriber Identity Model) is also called smart card, user identification card, GSM mobile phone must be installed with this card before it can be used. It can reliably guarantee the normal communication of users and prevent parallel phones and calls from being eavesdropped on. Both China Unicom and China Mobile have issued SIM cards for mobile phone users. SIM cards are also widely used in bank POS terminals. Therefore, corresponding SIM card holders have been extensively developed.
In the circuit design of the SIM card holder, in order to ensure the good function of the SIM card, the following design principles should be followed in the circuit design:
The distance between the SIM card holder and the module should not be too far, the closer the better. Ensure that the SIM card signal wiring does not exceed 20cm.
Keep the SIM card signal wire away from the RF wire and power wire.
The SIM signal line needs to be packaged. CLK and DATA wiring should not be too close to prevent crosstalk.
In order to ensure good ESD protection, it is recommended to add a TVS tube. The parasitic capacitance of the ESD device should not exceed 50pF. Place it near the SIM card slot.
Reserve 33pF capacitors on 4 important lines to filter out high-frequency interference. The capacitors are close to the SIM card slot.
The SIM power supply pin also needs to connect a bypass capacitor less than 1uF in parallel and be close to the SIM card slot.
Choose TXGA, a professional manufacturer of SIM card holders. Provide professional technical consulting services to avoid placing orders incorrectly and randomly. TXGA has advanced technology and strong strength, integrating connector research and development, production, sales and service. The quality is guaranteed, saving time and worry. Enter TXGA [Product Center], online ordering is more convenient.
