Telit Wireless Solutions GE863-QUAD Manual Do Utilizador

 
 
 
 

 

 

 1vv0300715 Rev. 1 - 19/09/06  

  

Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved 

 

page 17 of 79 

 

An example of linear regulator with 5V input is: 
 

 
 
 
 

4.2.1.2  + 12V input Source Power Supply Design Guidelines 

 
•  The desired output for the power supply is 3.8V, hence 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 especially with the 2A peak current 
load represented by the GE863-QUAD/PY. 

•  When using a switching regulator, a 500kHz or more switching frequency regulator is preferable 

because of its smaller inductor size and its faster transient response. This allows the regulator to 
respond quickly to the current peaks absorption.  

•  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 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. 

•  For Car applications a spike protection diode should be inserted close to the power input, in order 

to clean the supply from spikes.  

•  A protection diode should be inserted close to the power input, in order to save the GE863-

QUAD/PY from power polarity inversion. This can be the same diode as for spike protection.