User's Manual

LE920A4 HW User Guide Application Guide
Doc#: 1VV0301261 SIM Interface
Rev. 4.3 Page 105 of 123 2017-12-07
SIM Interface
This section presents the recommended schematics for the design of SIM interfaces on
the application boards. The module supports two external SIM interfaces.
11.3.1. SIM Schematic Example
Figure 29 illustrates in particular how to design the application side and which values to
assign the components.
Figure 29: SIM Schematics
NOTE:
The resistor value on SIMIO pulled up to SIMVCC must be defined to be
compliant with the 3GPP specification for USIM electrical testing.
The module contains an internal pull-up resistor of 20K Ω on SIMIO.
However, the un-mounted option in the application design can be
recommended to tune R1 if necessary.
The value of the C1 capacitor to be applied with the module is 100 nF.
EMC Recommendations
All signals in the module are provided with some EMC protection. Nevertheless, the
accepted level differs according to specific pin. Table 48 lists the characteristics.
Table 48: EMC Recommendations
Pad Signal I/O Function Contact Air
All pins
All pins All pins ± 4KV ± 8KV