CLM920_AC5 Mini PCIE LTE Module Hardware Manual
Shanghai Yuge Information Technology co., LTD
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Figure 3-13 USIM design circuit diagram
On the USIM interface line, it is recommended to select ONSEMI's SMF15C device for
ESD protection. The peripheral circuit devices should be placed close to the card holder.
The SIM card holder is close to the module layout.
The USIM card circuit is susceptible to radio frequency interference, causing card failure
or card dropping. Therefore, the card slot should be placed as far away as possible from
the antenna RF radiation, and the card wiring should be as far away from the radio
frequency, power supply and high-speed signal line as possible.
UIM_DATA has been internally pulled up to VDD_EXT through a 47K resistor, no
external pull-up is required.
UIM_DET is the detection pin inserted or not inserted into the USIM card. By default, it
is high level. This pin can be used to detect the SIM card status during hot-swap
applications.
In order to avoid instantaneous voltage overload, the USIM interface needs a 22R resistor
in series on the signal line path.
3.7.2 USIM_DET Hot Swap Reference Design
CLM920_AC5 Mini PCIE module supports SIM card hot swap function.
The USIM_DET pin is used as an input detection pin to judge whether the SIM card is
inserted or not. The UIM_DET pin is pulled high by default.
Table 3-10 Definition of SIM card hot swap detection pins
NO
UIM_DET status
Functional description
1
high
SIM card insertion, UIM_DET is high
