SEW290 WCDMA Module
13
4
Descriptions of Hardware Interfaces
4.1
Description
This section describes the function interfaces and usage of SEW290 module in details, and provides the
designing sample.
Power and Reset
UART
USIM
Audio
PCM
USB2.0
Antenna
Remarks: I
n the system, the module layout should be far away from high-speed circuit, switch power, power
transformer, large power inductor, or single chip microcomputer’s clock circuit.
4.2
Power and Reset
4.2.1
Power Design
The module could work under two modes: 1. powered by power adaptor; 2. powered by battery.
The EUT was suppliped by a special supply unit,which is connected to a pc via a usb port ,this
supply unit could be recognised as a power supply.The EUT worked at 3.4~4.2V DC.
The power could be directly supplied by external power, which is directly added to V_MAIN and satisfy the
voltage in the table 4-1. The external power could be power adaptor, battery, USB power convertor, etc. It’s
recommended that the safe power current is 2A to satisfy the GSM and GPRS mode.
Charge input: For some application with Li-battery, the Li-battery charge manage was embedded in Module,
please note the input charge voltage should be DC :5V
±
0.5V
Table 4-1 Voltage Features
Classification
Min.
Typical
Max.
Input voltage
3.
4
V
3.8 V
4.2 V
The supply power of Module should be DC from 3.3V to 4.2V,please refer to the following schematic to
design the power of Module:
