Telit Wireless Solutions CE910-DC, Hardware User'S Manual

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
The PCB traces to CE910 and the Bypass capacitor must be wide enough to ensure no
significant voltage drops occur when the 1A current peaks are absorbed. This is a must
for the same above-mentioned reasons. Try to keep this trace as short as possible.

The PCB traces connecting the switching output to the inductor and the switching diode
must be kept as short as possible by placing the inductor and the diode very close to the
power switching IC (only for switching power supply). This is done in order to reduce the
radiated field (noise) at the switching frequency (usually 100-500 kHz).

The use of a good common ground plane is suggested.

The placement of the power supply on the board must be done in a way to guarantee that
the high current return paths in the ground plane are not overlapped with any noise
sensitive circuitry such as the microphone amplifier/buffer or earphone amplifier.
The power supply input cables must be kept separate from noise sensitive lines such as
microphone/earphone cables.