Use Instructions

Table Of Contents
L710HG Hardware Design
22
Figure 3-4 Reference circuit of the DCDC power supply
Note: DCDC may deprave RF performance because of ripple current intrinsically.
3.4.5 Power Supply Layout guide
The layout of the power supply section and the related components is of vital importance in the power
module design. If processes this part layout is not good, will lead to various effects, such as bad EMC,
effective the emission spectrum and receiving sensitivity, etc. So the power supply part design is very
important, when you design this part you should notes below contents: 1. DC DC switch power should
place away from the antenna and other sensitivity circuit; 2. Consider the voltage drop and the module
current requirement, the layout line should better above 100mil. If conditions allow should add a
power shape plane.
3.5 UIM interface
3.5.1 Pin definition
The L710HG integrated a ISO 7816-2 standard USIM port, and only 1.8V SIM Cards are supported.
Table 3-9(a) (U)SIM card signal group definition and description
Pin No.
Signal name
I/O
Type Descriptions
16
USIM_VDD UIM Card Power output
15 USIM_PRESENT
USIM hot-plug detection (default low level
valid)
14
USIM_DATA
USIM Card data I/O, which has been
pulled up with a 10KR resistor to
USIM_VDD in module. Do not pull
up or pull down in users’ application
circuit.
12
USIM_CLK SIM clock signal
13
USIM_RST SIM reset signal
Table 3-9 (b) UIM Electronic characteristic (USIM_VDD =1.8V)
Symbol
Parameter
Min.
Typ.
Max.
Unit