N58 Hardware User Guide
Chapter 5 Application Interfaces
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Figure 5-1 Voltage drop of the power supply
Burst
Burst
0.577ms
T
2.038ms
Min: 3.3V
VBAT
VBAT
3.4V
Drop
It is forbidden to use the diode voltage step down method to supply power to the module. The forward voltage-
drop V
f
of the diode has two characteristics: one is that it increases as the forward current increases; the other is
that it increases significantly at low temperatures. If there is a large instantaneous current, these two
characteristics will cause the operating voltage of the module to be unstable and even damage the module.
The power supply design of the N58 module is determined by the power input voltage. The designs
are classified by power input voltage as follows:
3.4 V
–4.2 V power input (typical value 3.8 V, using the battery for power supply)
4.2 V
–5.5 V power input (typical value: 5.0 V, using the internal rectifier of the computer for
power supply)
5.5 V
–24 V power input (typical value: 12 V, typical industry: automotive industry)
The recommended 3.4 V
–4.2 V input design is as follows.
Figure 5-2 Recommended design 1
Power Supply
N58 Module
TVS
D1
C1
470uF
C2
10uF
C3
0.1uF
C4
100pF
Close to the pin of the module
VBAT
Test point
I_max
C5
33pF