User's Manual

UL865-N3G Hardware User Guide
1VV0301177 Rev 2– 2015-04-20
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Reserved. Page 27 of 70
Mod. 0805 2011-07 Rev.2
6.3.1.1. + 5V input Source Power Supply Design
Guidelines
 The desired output for the power supply is 3.8V, hence there's not a big difference
between the input source and the desired output and a linear regulator can be used. A
switching power supply will not be suited because of the low drop out requirements.
 When using a linear regulator, a proper heat sink shall be provided in order to
dissipate the power generated.
 A Bypass low ESR capacitor of adequate capacity must be provided in order to cut
the current absorption peaks close to the UL865-N3G V2, a 100μF tantalum capacitor
is usually suited.
 Make sure the low ESR capacitor on the power supply output (usually a tantalum
one) is rated at least 10V.
 A protection diode should be inserted close to the power input, in order to save the
UL865-N3G V2 from power polarity inversion.
An example of linear regulator with 5V input is: