ML6427

9

INPUTS

Bank A:

RGB, CV filtered path

Bank B:

RGB, CV filtered path

Other:

CV unfiltered path, Sync IN (slave mode)

Figure 4. Basic Application for NTSC

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 5. EVC (Enhanced Video Connector) Application: S-Video, Composite, plus H-Sync out

CVOUT1/YOUTA

21

H SYNC OUT

S-VIDEO

OUT

CHROMA

OUT

CHROMA IN

LUMA

OUT

LUMA IN

COMPOSITE

VIDEO OUT

TO EVC

CONNECTOR

COMPOSITE

VIDEO IN

CVOUT2/YOUTB

20

ROUT/YOUTC

18

23

24

1

13

14

19

5

17

22

6

GOUT/YOUTD

16

BOUT/COUT

15

CVINFA/Y2

3

GINA/Y6

9

GINB/Y7

10

BINA/C1

11

BINB/C2

12

RINA/Y4

7

RINB/Y5

8

CVINFB/Y3

4

CVINU/Y1

2

SYNCIN

SYNCOUT

SWAP CVF SWAP CVU

A/B MUX

GNDO

VCCORGB VCCOCV

VCC

GND

ML6427

MASTER

220µF

VIDEO CABLES

75

Ω

CV/Y

MODULATOR

220µF

75

Ω

R/Y

220µF

75

Ω

G/Y

220µF

75

Ω

B/C

H SYNC OUT

OPTIONAL FOR DC COUPLED APPLICATIONS

220µF

75

Ω

CV/Y

MODULATOR

CVOUT1/YOUTA

21

CVOUT2/YOUTB

20

ROUT/YOUTC

18

23

24

1

13

14

19

5

17

22

6

GOUT/YOUTD

16

BOUT/COUT

15

CVINFA/Y2

3

GINA/Y6

9

GINB/Y7

10

BINA/C1

11

BINB/C2

12

RINA/Y4

7

RINB/Y5

8

CVINFB/Y3

4

CVINU/Y1

2

SYNCIN

SYNCOUT

SWAP CVF SWAP CVU

A/B MUX

GNDO

VCCORGB VCCOCV

VCC

GND

ML6427

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.