Hardware Development Guide of Module Product
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48
MF206A
In poor situation of the network, the antenna will transmit at the maximum power, and the transient maximum
peak current can reach as high as 2A. So the power supply capacity of system board needs to be above 2.5A to
satisfy the requirement of module peak current; and the average current on the system side needs to be above
2.0A. Meanwhile, consider the voltage drop of power supply on the side of main board. If the network is in a
poor situation or under 2G, the module peak current will be great, Therefore the power supply has to be designed
in order to withstand with these current peaks without big voltage drops; this means that both the electrical
design and the board layout must be designed for this current flow. If the layout of the PCB is not well designed
a strong noise floor is generated on the ground and the supply; and exceptions such as restart of the module may
occur.
The peak current of ZTEWelink module under the GSM BURST mode is different due to the differences in
actual network environments. And its transient current under different powers will be various as well. The
greater the power is, the greater the transient current is. The network quality also directly affects the work
current of the module. If the network is in well situation, the peak work current on the module will be small. But
if the network is in poor situation, its peak current will be great as shown in Figure 4-1. When ZTEWelink
module works under the EDGE/GPRS Time Slot (2-high 6-low) and CLASS 10, if the module works under the
2-high work Time Slot, it requires greater current, and the voltage drop will occur accordingly.
Figure 4–1 Power Supply Current and Voltage Change under EDGE/GPRS
0
t/ms
0
0
Unit: 200mA/cell
Unit: V/cell
Voltage
Current
EDGE/GPRS TS
2-high 6-low
CLASS10
3.462ms
1.154ms
(577us/cell)
200mA
200mA
200mA
200mA
200mA
200mA
1V
2V
3V
3.6V
4.3
Circuit Requirements of Power Supply Output
Requirement
: