N723-EA Hardware User Guide
Chapter 5 Application Interfaces
Copyright © Neoway Technology Co., Ltd. All rights reserved.
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5
Application Interfaces
N723-EA provides the power, control, communication, audio, RF interfaces, and so on to meet the
functional requirements of customers in different application scenarios.
This chapter describes how to design each interface and provides reference designs and guidelines.
5.1
Power Interface
The schematic design and PCB layout of the power supply part are the most critical process in
application design and they will determine the performance of customers’ applications. Please read the
design guidelines of power supply and comply with the correct design principles to obtain the optimal
circuit performance.
Signal
Pin
I/O
Function description
Remarks
VBAT
27, 28, 29
PI
Power input of the module
V
min
= 3.4 V
V
norm
= 3.8 V
V
max
= 4.2V
VDD_1P8
45
PO
1.8 V power output
V
norm
= 1.8V
I
max
= 50 mA
GND
1, 14, 17, 20, 26, 30, 31, 44, 49, 74, 75, 77, 91,
93, 95, 97, 98, 99, 100
Ensure that all GND pins are
grounded.
5.1.1
VBAT
The power supply design covers two parts: schematic design and PCB layout.
Power Supply Design
In GSM/GPRS mode, RF data is transmitted in burst mode that generates voltage drops on the power supply.
Furthermore, this results in a 217 Hz TDD noise through the power and the transient peak current is 2 A.
Therefore, it is necessary to ensure that in the power supply design, the impedance of the power supply traces is
low, and there are large-capacity capacitors to improve the freewheeling capability to ensure that the voltage will
not drop below the minimum operating voltage of the module when the instantaneous current reaches its peak.
