EM1402 View Datasheet(PDF) - ProTek Devices.
Part Name
Description
Manufacturer
EM1402 Datasheet PDF : 6 Pages
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APPLICATION NOTE
The EM1402 provides a bidirectional filter and protector
for all the signals and the power line on the SIM (sub-
scriber indenty 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 Figure 1.
For best filter and ESD performance, both ground bumps
(B1, B2) of the EM1402 should be directly connected to
the ground plane. A small capacitor of about 1µF is
required next to the VCC pin of the SIM connector in order
to improve stability of the SIM card supply rail.
CIRCUIT BOARD LAYOUT RECOMMENDATIONS
Circuit board layout is critical for Electromagnetic
Compatibility (EMC) protection. The following guidelines
are recommended:
✔ The protection device should be placed near the
input terminals or connectors, the device will divert
the transient current immediately before it can be
coupled into the nearby traces.
✔ The path length between the TVS device and the
protected line should be minimized.
✔ All conductive loops including power and ground
loops should be minimized.
✔ The transient current return path to ground should be
kept as short as possible to reduce parasitic
inductance.
✔ Ground planes should be used whenever possible.
For multilayer PCBs, use ground vias.
Controller
with logic
level translator
EM1402
100 Ohm
SIM Card Connector
RST Reset
47 Ohm
CLK
Clock
100 Ohm
I/O
Data I/O
VCC
supply
(5V, 3.3V or 1.8V)
VCC
5V/3V/1.8V
1µF
GND
GND
Figure 1. Typical Application for SIM Card Interface
05219.R1 2/07
4
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