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 48 of 79 

 

The resulting gain and high pass cut can be obtained with the formula: 

2

3

=

 

 

4

*

3

*

2

1

.

π

=

 [Hz] 

And an example of internal Ear amplifier could be : 

 
Some amplifier require a low impedance load at high frequency in order to avoid auto oscillation, this 
can be made with a capacitor (100nF) in series with a resistor (15Ω). 
 
When designing your application, remember to provide an adequate bypass capacitor to the amplifier 
and place it close to the power input pin of the IC, keeping the traces as short as possible. 

8.5  Hands-Free Earphone (Low Power) Design 

The same design considerations made for the handset are valid for the hands-free earphone. 

+12dB

GE863-QUAD / PY