User's Manual

page 48/51
HiAll
NC
User Manual 2012/06/28
10.1.3 Clocks
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Clock signals must be shielded between two grounds layer and bordered with ground vias.
10.1.4 Data bus and other signals
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Data bus must be routed on the same layer with equivalent track length and avoiding long parallel routing.
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Lines crossings shall be perpendicular
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Suitable signals track width, thickness for other signals.
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Data bus must be protected by upper and lower ground plans
10.1.5 Radio
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Provide a 50 Ohm micro strip line for antenna connection
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For RF matching components do not locate matching inductors too close to shield walls (this may cause
electromagnetic coupling and inductor de-Q).
10.1.6 Audio
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Differential signals have to be routed together, parallel (for example HSET_OUT_P/HSET_OUT_N,
MIC_P/MIC_N).
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Audio signals have to be isolated, by pair, from all the other signals (ground all around each pair).
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Cancel any loops between VBAT and GND next to the speaker to avoid the TDMA burst noise in the
speaker during a communication.
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The single-end audio signal should be adopted the same rules as differential signals.
Figure 30: Layout of audio differential signals on a layer n
Figure 31: Adjacent layers of audio differential signals
Layer n-1
Layer n
Layer n+1
GND
HSET_OUT_P
GND
GND
HSET_OUT_P
GND
HSET_OUT_N