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L830-EB-11 Hardware User Manual
Page 22 of 39
Figure 3-10 Reference Circuit for USB 2.0 Interface
Since the module supports USB 2.0 High-Speed, it is required to use TVS diodes with equivalent
capacitance of 1pF or smaller ones on the USB_D-/D+ differential signal lines, it is recommended to use
0.5pF TVS diodes.
USB_D- and USB_D+ are high speed differential signal lines with the maximum transfer rate of 480 Mbit/s,
so the following rules shall be followed carefully in the case of PCB layout:
USB_D- and USB_D+ signal lines should have the differential impedance of 90 ohms.
USB_D- and USB_D+ signal lines should be parallel and have the equal length, the right angle
routing should be avoided.
USB_D- and USB_D+ signal lines should be routed on the layer that is adjacent to the ground
layer, and wrapped with GND vertically and horizontally.
3.5
USIM Interface
The L830 module supports USIM card interface including 1.8V and 3V SIM cards.
3.5.1 USIM Pins
The USIM pins description as shown in the following table:
Pin Pin Name
I/O Reset Value Description
Type
36
UIM_PWR
PO
USIM power supply
1.8V/3V
30
UIM_RESET
O
L
USIM reset
1.8V/3V
32
UIM_CLK
O
L
USIM clock
1.8V/3V
34
UIM_DATA
I/O
L
USIM data, internal 4.7K pull-up
1.8V/3V
