User's Manual

720 Hardware User Guide

lines adopt differential trace design, in which the differential impedance is limited to 90 

characteristics impedance. Isolate the traces from other signal traces.

2.5 UIM Card Interface

Name Pin I/O Function Remarks

VUIM 35 PO UIM power supply output

Compatible with 1.8/3 V

UIM card

UIM_DATA 36 IO UIMdata I/O

A 10K resistor is required

between VUIM and

UIM-DATA.

UIM_CLK 37 DO UIMclock output

UIM_RESET 38 DO UIMreset

UIM_DETECT 39 DI UIM detect

Advise to use a pull-up

resistor

N720 supports 1.8V/3V UIM cards.. VUIM is the power supply pin of the UIM card and its

maximum load is 30 mA. The UIM_DATA pin is not pulled up internally, so you need to reserve

external pull-up resistor in your design. UIM_CLK is the clock signal pin, supporting 3.25 GHz of

clock frequency. Figure 2-15 shows the reference design of the UIM card interface.

Figure 2-15 Reference design of SIM card interface