Quectel BG96 Mini PCIe Hardware Design page 20

If (U)SIM card detection function is not needed, please keep USIM_PRESENCE pin unconnected. A
reference circuit for (U)SIM interface with a 6-pin (U)SIM card connector is illustrated in the following
figure.
Module
GND
USIM_VDD
USIM_RST
USIM_CLK
USIM_DATA
Figure 5: Reference Circuit of a 6-Pin (U)SIM Card Connector
In order to enhance the reliability and availability of the (U)SIM card in customers' applications, please
follow the criteria below in (U)SIM circuit design:

Keep placement of (U)SIM card connector to the module as close as possible. Keep the trace length
as less than 200mm as possible.

Keep (U)SIM card signals away from RF and power supply traces.

Assure the ground between the module and the (U)SIM card connector short and wide. Keep the
trace width of ground no less than 0.5mm to maintain the same electric potential. The decouple
capacitor between USIM_VDD and GND should be not more than 1μF and be placed close to the
(U)SIM card connector.

To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with surrounded ground.

In order to offer good ESD protection, it is recommended to add a TVS whose parasitic capacitance
should not be more than 15pF. The 0Ω resistors should be added in series between the module and
the (U)SIM card so as to facilitate debugging. The 33pF capacitors are used for filtering interference
of EGSM900. Please note that the (U)SIM peripheral circuit should be close to the (U)SIM card
connector.

The pull-up resistor on USIM_DATA line can improve anti-jamming capability when long layout trace
and sensitive occasion are applied, and should be placed close to the (U)SIM card connector.
BG96_Mini_PCIe_Hardware_Design
USIM_VDD
15K
0R
0R
0R
33pF 33pF 33pF
GND
LTE Module Series
BG96 Mini PCIe Hardware Design
100nF
(U)SIM Card Connector
VCC
RST
CLK
GND
GND
VPP
IO
19 / 40