Neoway N75 - 3 Application Interfaces; Power Interface; Vbat

N75
Hardware User Guide
Copyright © Neoway Technology Co., Ltd
14
3 Application Interfaces
N75 provides power supply, control, communications, network and connection, RF, and other interfaces
to meet customers requirements in different application scenarios.
This chapter describes how to design each interface and provides reference designs and guidelines.
3.1 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
Remarks
VBAT
27, 28, 29
PI
Main power supply input
3.3V~4.3V (TYP: 3.8V)
VDDIO_1P8
45
PO
1.8V power output
Output 50 mA at most, used only for
level shifting.
Add ESD protector when using this pin.
VDDXO_1P8
53
PO
1.8V power output
Used only to connect WLAN oscillator
through a pull-up resistor
Do not use this pin to load any
components.
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.
3.1.1 VBAT
VBAT is the power supply input of the module. Its input voltage ranges from 3.3V to 4.3V and the
preferable value is 3.8V. In addition to baseband, it supplies power for RF power amplifier.The
performance of the VBAT power supply is a critical path to module's performance and stability.
The peak input current at the VBAT pin can be up to 2 A when the signal is weak and the module works
at the maximum transmitting power in GSM/GPRS mode. The voltage will encounter a drop in such a
situation. The module might restart if the voltage drops lower than 3.3V. Figure 3-1 Shows the current
peaks and voltage drop.