ML6427
TYPICAL APPLICATIONS
(Continued)
USING THE ML6427 FOR PAL APPLICATIONS
The ML6427 can be optimized for PAL video by adding
frequency peaking to the composite and S-video outputs.
Figure 10 illustrates the use of an additional external
capacitor (330pF) in parallel with the output source
termination resistor. This raises the frequency response
from 1.6dB at 4.8MHz to 0.35dB at 4.8MHz, which
allows for accurate reproduction of the upper sideband of
the PAL subcarrier. Figure 11 shows the frequency
response of PAL video with various values of peaking
capacitors (220pF, 270pF, 330pF and none) between 0 and
10MHz.
For NTSC applications without the peaking capacitor the
rejection at 27MHz is 42dB (typical). For PAL applications
with the peaking capacitor the rejection at 27MHz is 38dB
(typical). See Figure 12. The differential group delay,
shown in Figure 13 with and without a peaking capacitor
(220pF, 270pF, and 330pF and none), varies slightly with
capacitance from 8ns to 13ns.
2
3
4
7
8
9
10
11
12
19
GNDO
CVINU/Y1
CVINFA/Y2
CVINFB/Y3
RINA/Y4
RINB/Y5
GINA/Y6
GINB/Y7
BINA/C1
BINB/C2
SYNCIN
23
5
GND
17
VCCORGB
22
VCCOCV
6
VCC
CVOUT1/YOUTA
21
220µF
75Ω
VIDEO CABLES
CV/Y
MODULATOR
220µF
CVOUT2/YOUTB
ML6427
ROUT/YOUTC
GOUT/YOUTD
BOUT/COUT
SYNCOUT
24
A/B MUX
1
SWAP CVF SWAP CVU
13
14
220µF
18
220µF
16
220µF
15
75Ω
CV/Y
20
75Ω
MODULATOR
R/Y
75Ω
G/Y
75Ω
B/C
OPTIONAL FOR DC COUPLED APPLICATIONS
H SYNC OUT
INPUTS
Bank A:
Bank B:
Other:
RGB, CV filtered path
RGB, CV filtered path
CV unfiltered path, Sync IN (slave mode)
OUTPUTS
Option 1:
2 CV outputs + 2 TV modulator outputs, 1 RGB output
Option 2:
2 CV outputs + 1 TV modulator output, 1 S-video output
Other:
Sync output (buffered stripped sync)
Figure 4. Basic Application for NTSC
19
GNDO
CVINU/Y1
CVINFA/Y2
CVINFB/Y3
RINA/Y4
RINB/Y5
GINA/Y6
GINB/Y7
BINA/C1
BINB/C2
SYNCIN
23
SYNCOUT
24
A/B MUX
1
ML6427
MASTER
CVOUT2/YOUTB
20
LUMA
OUT
S-VIDEO
OUT
CHROMA
OUT
TO EVC
CONNECTOR
5
GND
17
VCCORGB
22
VCCOCV
6
VCC
CVOUT1/YOUTA
21
2
COMPOSITE
VIDEO IN
3
4
LUMA IN
7
8
9
10
CHROMA IN
11
12
COMPOSITE
VIDEO OUT
ROUT/YOUTC
GOUT/YOUTD
BOUT/COUT
SWAP CVF SWAP CVU
13
14
18
16
15
H SYNC OUT
Figure 5. EVC (Enhanced Video Connector) Application: S-Video, Composite, plus H-Sync out
9
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
