MAX9598 Maxim Integrated Products, MAX9598 Datasheet - Page 26

• Manufacturer Part Number: MAX9598
• Description: Low-Power Audio/Video Switch
• Manufacturer: Maxim Integrated Products

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The MAX9598 features single 3.3V and 12V supply
operation and requires no negative supply. The 12V
supply, V12 is for the SCART switching function. For
V12, place a 0.1µF bypass capacitor as close as possi-
ble. Connect all VAUD pins together to 3.3V and bypass
with a 10µF electrolytic capacitor in parallel with a 0.1µF
ceramic capacitor to audio ground. Bypass each VVID
to video ground with a 0.1µF ceramic capacitor.
The MAX9598 was designed to operate from noisy digital
supplies. The high PSRR (49dB at 100kHz) allows the
MAX9598 to reject the noise from the digital power sup-
plies (see the Typical Operating Characteristics ). If the
digital power supply is very noisy and stripes appear on
the television screen, increase the supply bypass capaci-
tance. An additional, smaller capacitor in parallel with the
main bypass capacitor can reduce digital supply noise
because the smaller capacitor has lower equivalent series
resistance (ESR) and equivalent series inductance (ESL).
Low-Power Audio/Video Switch for
Dual SCART Connectors
26
Table 8. Data Format for Write Mode
(HEXADECIMAL)
REGISTER
ADDRESS
______________________________________________________________________________________
0Ah
0Bh
0Ch
0Dh
00h
01h
02h
03h
04h
05h
06h
07h
08h
09h
10h
VCR_R/C_IN
VCR_Y/CV
Not used
Not used
Not used
Not used
Not used
BS_OUT
enable
Clamp
BIT 7
Operating mode
Power-Supply Bypassing
Using a Digital Supply
VCR_R/C_
Not used
Not used
Not used
Not used
enable
BIT 6
ZCD
OUT
Not used
OUT enable
Not used
Not used
Not used
Not used
TV_R/C_
BIT 5
TV_G_OUT
TV G and B video switch
Not used
Not used
Interrupt
enable
enable
Set TV fast switching
BIT 4
For optimal performance, use controlled-impedance
traces for video signal paths and place input termina-
tion resistors and output back-termination resistors
close to the MAX9598. Avoid routing video traces paral-
lel to high-speed data lines.
The MAX9598 provides separate ground connections
for video and audio supplies. For best performance,
use separate ground planes for each of the ground
returns and connect all ground planes together at a sin-
gle point. Refer to the MAX9598 Evaluation Kit for a
proven PCB layout example.
If the MAX9598 is mounted using flow soldering or wave
soldering, the ground via(s) for the exposed pad should
have a finished hole size of at least 14 mils to ensure
adequate wicking of soldering onto the exposed pad. If
the MAX9598 is mounted using solder mask technique,
the via requirement does not apply. In either case, a
good connection between the exposed pad and ground
is required in order to minimize noise from coupling onto
the outputs.
Not used
Not used
Not used
Not used
Not used
Not used
Not used
ENC_R/C_IN
TV_B_OUT
Not used
Not used
enable
clamp
BIT 3
VCR audio selection
Not used
TV_Y/CVBS_
OUT ground
OUT enable
VCR_R/C_
Not used
BIT 2
Layout and Grounding
VCR video switch
TV video switch
TVOUT_FS
Set TV slow switching
TV audio selection
enable
BIT 1
Set VCR slow
switching
Not used
TV audio
output
BIT 0
mute