Data Sheet

Page 16
Layer 3
X
Power supply/signal
routing
Analogy power
supply/signal routing
Layer 4
X
Power supply/signal
routing/GND
GND
Layer 5
X X
Digital power supply/signal
routing
Layer 6
X X
GND
■ The characteristic impedance of the RF signal traces must be 50 ohm
.
■ 4L PCB RF foot Pad must keep out
>
=10mil in the TOP layer
,
and for Pad with larger width
(>
=1
.
3
times line width
),
the GND of L2 just under it must be hollowed out with equal area
,
as shown below
.
■ 2L PCB RF wire must be covered with copper foil
,
and the copper spacing is recommended to be 4mil
■ 3
.
3V voltage regulator supply to the module
,
power supply pin routing should be as thick as possible
and short circuit resistance should be as much as possible <0
.
05 ohm
.
■ 10uF power supply capacitance must be placed close to the module pin
.
■ SDIO traces
：
1
.
Keep the characteristic impedance of SDIO traces ~50 ohm
.
2
.
The traces
(
CLK
,
CMD
,
D0~D3
)
difference shall be kept +/-100 mil
,
the total length shall be ＜2
.
5
inches
.
3
.
All traces shall go along with the reference GND
,
and there must be no shunt stubs on those traces
.
4
.
There must be less than 4 via on each signal trace
(
CLK
,
CMD
,
D0~D3
).