CM1402_11 Datasheet, PDF (6/8 Pages) ON Semiconductor – SIM Card EMI Filter Array ESD Protection

CM1402
APPLICATION INFORMATION
The CM1402 provides a bidirectional filter and protector for all the signals and the power line on the SIM (subscriber
identity module) card connector. SIM cards are found in all GSM cellular phones and in some other handheld devices or card
readers. The ESD diodes protect the controller against possible ESD strikes that may occur when the connector pins are
exposed during direct contact, or during insertion of the SIM card into the card slot. The EMI filter suppresses all
high−frequency noise, preventing the unwanted EMI signals from both entering and exiting the main board. The signals that
interface with the SIM card are the Reset, the Clock and the bidirectional data I/O, as shown in Typical Application Diagram
for the SIM Card Interface.
Note: One channel of the CM1402 with a zener diode is
not shown on the diagram.
Figure 5. Typical Application Diagram for the SIM Card Interface
For best filter and ESD performance, both GND bumps (B1, B2) of the CM1402 should be directly connected to the
Ground plane. A small capacitor of about 1 mF is required next to the V_CC pin of the SIM connector in order to improve
stability of the SIM card supply rail.
For information on the assembly of the CM1402 to the PCB (printed circuit board), please refer to the Chip Scale Package
(CSP) Application Note AP217, or contact factory at 800−282−9855 for technical support.
http://onsemi.com
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