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ADV7170/ADV7171
Rev. C | Page 39 of 64
75
Ω
75
Ω
75
Ω
75
Ω
150
Ω
5k
Ω
5k
Ω
5V (VCC)
100
Ω
100
Ω
MPU BUS
10, 19, 21,
29, 43
27
DAC D
26
DAC C
31
DAC B
32
DAC A
23
SCLOCK
24
SDATA
34
RSET
1, 11, 20, 28, 30
VAA
ADV7170/
ADV7171
25
COMP
33
VREF
35
SCRESET/RTC
15
HSYNC
16
FIELD/VSYNC
17
BLANK
22
RESET
37
TTX
36
TTXREQ
44
CLOCK
P15–P0
38–42,
2–9, 12–14
18
ALSB
GND
5V (VAA)
0.1
μF
0.1
μF
UNUSED
INPUTS
SHOULD BE
GROUNDED
10k
Ω
5V (VAA)
27MHz CLOCK
(SAME CLOCK AS USED BY
MPEG2 DECODER)
TELETEXT PULL-UP AND
PULL-DOWN RESISTORS
SHOULD ONLY BE USED
IF THESE PINS ARE NOT
CONNECTED
100nF
5V (VAA)
4k
Ω
5V (VCC)
100k
Ω
100k
Ω
RESET
TTX
TTXREQ
POWER SUPPLY DECOUPLING
FOR EACH POWER SUPPLY GROUP
0.1
μF
0.01
μF
10
μF
5V (VAA)
L1
(FERRITE BEAD)
33
μF
5V
VCC
GND
S-VIDEO
00221-054
Figure 54. Recommended Analog Circuit Layout
The circuit in
Figure 55 can be used to generate a 13.5 MHz waveform using the 27 MHz clock and the HSYNC pulse. This waveform is
guaranteed to produce the 13.5 MHz clock in synchronization with the 27 MHz clock. This 13.5 MHz clock can be used if a 13.5 MHz
clock is required by the MPEG decoder. This guarantees that the Cr and Cb pixel information is input to the ADV7170/ADV7171 in the
correct sequence.
D
Q
CK
D
Q
CK
CLOCK
HSYNC
13.5MHz
00221-055
Figure 55. Circuit to Generate 13.5 MHz