Analog Ground - Motorola G24 Developer's Manual

The following guidelines should be followed to achieve best audio performance:
•
Reference the microphone input circuits to the G24 AGND interface signal.
•
If using single-ended audio outputs, they should be referenced to the G24 AGND interface
signal.
•
Keep the audio circuits away from the antenna.
•
Use RF filtering capacitors on the audio signals, as described in
•
The audio signals should not be routed adjacent to digital signals.
•
Isolate the audio signals by a surrounding ground plane or shields.
•
Filter internal supplies and signals that may indirectly affect the audio circuits, from noises
and voltage drops.

Analog Ground

The G24 interface incorporates a dedicated analog ground contact, AGND pin 61, which is
internally connected to the G24's ground. The AGND signal is intended to provide a separate
ground connection for the application's external audio devices and circuits.
This signal provides an isolated ground connection directly from G24, which is separated from
the noisy digital ground of the application. It is recommended to connect this signal to analog
audio devices and circuits used by the application. Using a separate analog ground minimizes
audio noises and improves the audio circuit's immunity from external interferences.
January 1, 2006 Module Hardware Description
Chapter 2: Hardware Interface Description
Table 2-3.
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