MAX9670CTL+T Maxim Integrated Products, MAX9670CTL+T Datasheet - Page 27

• Manufacturer Part Number: MAX9670CTL+T
• Description: IC AUDIO/VIDEO SWIT DUAL 40TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX9670CTL+T

• Function: Audio/Video Switch
• Circuit: 2 x SCART
• Voltage Supply Source: Single Supply
• Voltage - Supply, Single/dual (±): 3.3 V ~ 12 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 40-WFQFN Exposed Pad
• For Use With: MAX9670EVKIT+ - EVALUATION KIT FOR MAX9670
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Similarly, when YPbPr signals are desired, ENC_R/C_IN,
ENC_G_IN, and ENC_B_IN of the MAX9670/MAX9671
should be set to high-impedance mode by setting bit 4 in
register 08h to high if those video inputs are AC-coupled.
The high-impedance mode has higher priority whether
ENC_R/C_IN is in sync-tip clamp or bias circuit mode
(set by bit 3 in register 08h). If ENC_R/C_IN, ENC_G_IN,
and ENC_B_IN are DC-coupled, the inputs should be left
in sync-tip clamp mode. The RGB outputs of the
MAX9670/MAX9671 should be muted or shut down.
In either case, the inactive device should not distort the
video signals generated by the DACs.
The MAX9670/MAX9671 feature single 3.3V and 12V
supply operation and require no negative supply. The
12V supply V
V
ble. Connect all V
with a 10µF electrolytic capacitor in parallel with a
0.1µF ceramic capacitor to audio ground. Bypass each
V
The MAX9670/MAX9671 are designed to operate from
noisy digital supplies. The high PSRR (49dB at 100kHz)
allows the MAX9670/MAX9671 to reject the noise from
the digital power supplies (see the Typical Operating
Characteristics ). If the digital power supply is very noisy
Figure 19. Triple DAC is connected to both a MAX9670/MAX9671 and a MAX9653/MAX9654 high-definition video-filter amplifier. (A)
The MAX9670/MAX9671 are transmitting standard-definition RGB signals while the MAX9653/MAX9654 are in shutdown mode. (B)
The MAX9670/MAX9671 are not transmitting RGB signals, but the MAX9653/MAX9654 are transmitting high-definition YPbPr signals.
12
VID
, place a 0.1µF bypass capacitor as close as possi-
SET-TOP BOX
to video ground with a 0.1µF ceramic capacitor.
CHIP
DAC
DAC
DAC
Volume Control for Dual SCART Connectors
Low-Power Audio/Video Switch with Audio
12
3.3V
3.3V
3.3V
is for the SCART switching function. For
AUD
______________________________________________________________________________________
pins together to 3.3V and bypass
Power-Supply Bypassing
0.1µF
0.1µF
0.1µF
(A)
INPUTS SET TO SYNC-TIP CLAMP
ENC_R/C_IN
ENC_G_IN
ENC_B_IN
PBIN
PRIN
SHDN
YIN
Using a Digital Supply
MAX9670/MAX9671
MAX9653
MAX9654
OFF
TV_R/C_OUT
TV_G_OUT
TV_B_OUT
PBOUT
PROUT
YOUT
75Ω
75Ω
75Ω
75Ω
75Ω
75Ω
YPbPr OUTPUTS
SCART
CONNECTOR
and stripes appear on the television screen, increase
the supply bypass capacitance. 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).
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 MAX9670/MAX9671. Avoid routing video
traces parallel to high-speed data lines.
The MAX9670/MAX9671 provide separate ground con-
nections for video and audio supplies. For best perfor-
mance, use separate ground planes for each of the
ground returns and connect all ground planes together
at a single point. See the MAX9670/MAX9671 evalua-
tion kit for a proven circuit board layout example.
If the MAX9670/MAX9671 are mounted using flow sol-
dering or wave soldering, the ground via(s) for the EP
pad should have a finished hole size of at least 14mils
to insure adequate wicking of soldering onto the
exposed pad. If the MAX9670/MAX9671 are 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 to minimize
noise from coupling onto the outputs.
SET-TOP BOX
CHIP
DAC
DAC
DAC
3.3V
3.3V
3.3V
3.3V
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
(B)
INPUTS SET TO HIGH IMPEDANCE
ENC_R/C_IN
ENC_G_IN
ENC_B_IN
PBIN
PRIN
SHDN
YIN
Layout and Grounding
MAX9670/MAX9671
MAX9653
MAX9654
ON
TV_R/C_OUT
TV_G_OUT
TV_B_OUT
PBOUT
PROUT
YOUT
75Ω
75Ω
75Ω
75Ω
75Ω
75Ω
YPbPr OUTPUTS
SCART
CONNECTOR
27