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Advantech SOM-Express Design Guide
Chapter 5 Carrier Board Design Guidelines
55
SOM-Express
Audio Codec
(down)
Modem
Codec
Audio
Codec
CONN
Q
Swi
tc
h
CONN
Carrier board
MDC
Dock
R1
R2
R3
L1
L2
L2
L3
L2 L3 L4
L2 L5 L6
Figure 5-17 Azalia – AC_SDOUT/AC_SYNC/AC_BITCLK/AC_RST# Topology#1
Table 5.12 Azalia – AC_SDOUT/AC_SYNC/AC_ BITCLK/AC_RST# Topology #1
Trace
Impedance
Azalia Requirements
Trace
length
Series
Termination
Resistance
Signal
Length
Matching
55
Ω
+/- 15%
4 on 7 (stripline)
5 on 7 (microstrip)
L1= 1“ – 11“
L2= 0.5“
L3= 1“ – 15“
L4= 1.5“
L5
≤
0.5“
L6= 5“
R1= 33
Ω
+/- 5%
R2= 39
Ω
+/- 5%
R3= 39
Ω
+/- 5%
N/A
SOM-Express
Audio Codec
(down)
Modem
Codec
Audio
Codec
CONN
Q
Swit
ch
CONN
Carrier board
L3
R1
L2
L1 L2 L8 L2 L4 L5
R4 R2
L2
R3
L4 L6 L7
MDC
Dock
Figure 5-18 Azalia – AC_SDOUT/AC_SYNC/AC_BITCLK/AC_RST# Topology#2