Telit Wireless Solutions NE310L2, Руководство по конструкции аппаратуры

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NE310L2 Hardware Design Guide
1VV0301711 Rev. 2 Page 23 of 64 2021-06-22
An example of linear regulator with 5V input is:
Figure 2 : example of linear regulator with 5V input
4.3.1.2. +12V Source Power Supply Design Guidelines
 The desired output for the power supply is 3.8V, so due to the big difference
between the input source and the desired output, a linear regulator is not suited
and shall not be used. A switching power supply will be preferable because of its
better efficiency.
 When using a switching regulator, a 500kHz or higher switching frequency
regulator is preferable due to its smaller inductor size and its faster transient
response. This allows the regulator to respond quickly to the current peaks
absorption.

In any case the frequency and Switching design selection is related to the
application to be developed since the switching frequency could also generate
EMC interferences.
 For car PB battery the input voltage can rise up to 15,8V and this should be kept in
mind when choosing components: all components in the power supply must
withstand this voltage.
 A Bypass low ESR capacitor of adequate capacity must be provided in order to cut
the current absorption peaks, a 100
μ F capacitor is usually suitable.
 Make sure the low ESR capacitor on the power supply output has a nominal voltage
of at least 10V.