LE910Cx HW User Guide
1VV0301298 Rev. 33
Page 102 of 128
2021-06-29
Not Subject to NDA
Bypass capacitors are needed to alleviate this behaviour. The behaviour can appear
differently depending on the various applications. Customers need to pay special
attention to this issue when designing their application board. The length and width of the
power lines must be carefully considered, and the capacitance of the capacitors must be
selected accordingly. The capacitor will also prevent power supplies ripple and switching
noise caused in TDMA systems, such as GSM.
Especially, a suitable bypass capacitor must be mounted on the following lines on the
application board:
•
VBATT & VBATT_PA (M1, M2, N1, N2, P1, P2)
•
USB_VBUS (Pad A13)
Recommended values are:
•
100uF for both VBATT and VBATT_PA together
•
4.7uF for USB_VBUS (including the 1uF capacitor inside the module)
Customers must still consider that the capacitance mainly depends on the conditions of
their application board.
Generally, more capacitance is required when the power line is longer.
SIM Interface
This section presents the recommended schematics for the design of SIM interfaces on
the application boards. The LE910Cx supports two external SIM interfaces.
11.3.1.
SIM Schematic Example
Figure 35 illustrates in particular how to design the application side and what values to
assign the components.
Figure 36: SIM Schematics
