N21
Hardware User Guide
Copyright © Neoway Technology Co., Ltd. All rights reserved.
7
3 Application Interfaces
N21 provides power supply, communications, 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 Supply
The schematic design and PCB layout of the power supply part are the most critical process in
application design and they determine the performance of customers application. Please read the
guidelines to design power supply and comply with the correct design principles to obtain the optimal
circuit performance.
Signal
Pin I/O Function
Remarks
VBAT
2, 3 PI
Main power input
3.1V to 4.3V (TYP: 3.6V)
VDDIO_2P8 17
PO 2.8V power output
Output max. 50 mA, used only for level shifting.
Add ESD protector when using this pin.
GND
1, 4, 10, 21
Connect all GND pins to the ground plane.
3.1.1 VBAT
The power supply design consists of two parts: schematic design and PCB layout.
Schematic Design
N21 adopts a 3.3V-4.3V voltage input supplied by a battery and the typical voltage is 3.6V. Figure 3-1
Shows the schematic design of N21 power supply.
