N58 Hardware User Guide
Chapter 5 Application Interfaces
Copyright © Neoway Technology Co., Ltd. All rights reserved.
30
The maximum input voltage for the module is 4.2 V, and the typical value is 3.8 V; the VBAT-
recommended PCB trace width is greater than or equal to 2.5 mm.
The reverse working voltage VRWM of TVS D1 is 4.5 V, and the peak power Ppp is 2800 W (tp =
8/20 uS). TVS is used for power surge protection. Place TVS close to the input interface of the
power supply so that the power surge voltage is clamped before it enters back-end circuits,
protecting the back-end components and the module.
A large-
capacity tantalum electrolytic capacitor (220 μF or 100 μF) or aluminum electrolytic
capacitor (470 μF or 1000 μF) can be selected at C1 to improve the instantaneous large current
freewheeling capability of the power supply. Its withstand voltage must be greater than 2 times
the voltage of the power supply.
Place low-ESR bypass capacitors (C2, C3, C4, and C5) close to the module to filter out high-
frequency interference from the power supply.
The following circuit design is recommended if the power supply needs to be controlled.
Figure 5-3 Recommended design 2
S
G
D
R4
100 k
Ω
C4
10
μ
F
Q2
Q1
C3
470
μ
F
C5
0.1
μ
F
C6
100pF
C7
33 pF
R1
4.7 k
Ω
R2
47 k
Ω
C1
22
μ
F
C2
0.1
μ
F
B
C
E
VIN (3.8V)
VBAT
PWR_EN
C8
R5
10 k
Ω
C9
Select an enhanced P-MOSFET at Q1, and the component must be of high withstand voltage
(V
dss
= -12 V), high drain current (I
D(MAX)
= -3.5 A), and low DC resistance (R
ds(on)
= 108 mΩ).
Select a common NPN triode or a digital NPN triode at Q2. It is recommended that the
resistance of R2 should be at least 10 times the resistance of R1, especially for the situation in
which the base conduction voltage of the triode increases in a low temperature.
Place C3 close to the module. A large-
capacity tantalum electrolytic capacitor (220 μF or 100 μF)
or aluminum electrolytic capacitor (470 μF or 1000 μF) can be selected to improve the
instantaneous large current freewheeling capability of the power supply. Its withstand voltage
must be greater than 2 times the voltage of the power supply.
Place low-ESR bypass capacitors (C4, C5, C6, and C7) close to the module to filter out high-
frequency interference from the power supply.
The recommended 4.2 V
–5.5 V input design is as follows.
