User's Manual

HC864-AUTO Hardware User Guide
1vv0300946 Rev.4 – 2012-12-27
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 28 of 77
Therefore the power supply has to be designed in order to withstand these current peaks
without big voltage drops; this means that both the electrical design and the board layout must
be designed for this current flow. If the layout of the PCB is not well designed, a strong noise
floor is generated on the ground; this will reflect on all the audio paths producing an audible
annoying noise at 216 Hz; if the voltage drops during the peak, current absorption is too much.
The device may even shut down as a consequence of the supply voltage drop.