CM1402
Application Information
The CM1402 provides a bidirectional filter and protector
for all the signals and the power line on the SIM (sub-
scriber identity module) card connector. SIM cards are
found in all GSM cellular phones and in some other hand-
held 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 con-
tact, or during insertion of the SIM card into the card slot.
The EMI filter suppresses all high-frequency noise, pre-
venting 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
CM1402
100ohm
SIM Card Connector
RST
Reset
47ohm
CLK
Clock
Controller
with logic
level
translator
100ohm
I/O
Data I/O
VCC
supply
(5V,
3.3V or
1.8V)
GND
Note: One channel of the CM1402 with a zener
diode is not shown on the diagram.
VCC
5V/3V/1.8V
1uF
GND
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
μ
F 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 con-
tact factory at 800-325-4966 for technical support.
© 2005 California Micro Devices Corp. All rights reserved.
6
490 N. McCarthy Blvd., Milpitas, CA 95035-5112
●
Tel: 408.263.3214
●
Fax: 408.263.7846
●
www.cmd.com
11/02/05
CALMIRCO [ CALIFORNIA MICRO DEVICES CORP ]
