Shenzhen Coban Electronics Co. Ltd. CB900 用户手册
Pin Description
Electrical Characteristics
Figure 6: KEY Power ON reference circuit
Boot timing diagram is as following:
Figure 7: Boot timing diagram
4.7. Subscriber Identity Module (SIM) Interface
The SIM card interface is composed of an internally dedicated voltage regulator and I/O level
shifters. It is able to support both 1.8V and 3V SIM cards. It is recommended that the routing
traces of the SIM interface lines be kept as short as possible. ESD diodes can be added to the
signals connected to the SIM socket to prevent any ESD-related issues. The diodes shall be placed
as close to the SIM socket as possible. Also, a decoupling capacitor of about 100nF should be
added on the VSIM1 line near the SIM socket. At any point of time, only one SIM card is to be
connected as the same pins of both (SIM holder placed on top of the module, external SIM holder)
are shorted.
Pin Description
Parameters
Min
Type
Max
Unit
High level input voltage, VIH
2
-
-
V
Low level input voltage, VIL
-
-
-0.805
V
Pin
Signal Name
Signal I/O
Description
27
VSIM1
O
SIM card supply voltage, the module