ML6426

DATA SHEET

8

REV. 3A August 2004

Pixel clock rates for the output D/A converters can be

roughly determined from the Table 1. Don’t forget that the

deflection system of a CRT display needs retrace time for the

vertical and horizontal.

This retrace time can vary from one design of an HDTV set

to another, as it only involves tradeoffs between the frame

buffer in the MPEG decoder and the CRT deflection system.

Allowing for 10% retrace time for the vertical and 20% for

the horizontal, the appropriate Reconstruction Filter is sum-

marized in Table 2.

For VGA or RGB monitors, the following resolutions can

use the corresponding Reconstruction Filter and Video

Amplifier as shown in Table 3.

Figures 4, 5, and 6 show system diagrams when the ML6426

provides a good solution. Figure 7 provides a more detailed

description for advanced TV applications using various reso-

lutions for legacy video, SDTV, and HDTV.

Using the ML6426 in Multiple Resolutions

Several ML6426 devices can be used in parallel to construct

a selectable filter selection block ranging from frequencies

between 6.7 MHz to 50MHz. Each ML6426 can be individu-

ally controlled via the disable pin. In a parallel configuration,

as shown in Figure 3 and 7, several ML6426 devices can be

used and selected via general purpose I/O or other logic to

perform the proper reconstruction filtering for the resolution

of choice. This configuration allows for a minimum of bill of

materials and reduces cost. Fairchild’s ML6426 EVAL Kit

demonstrates multi-resolution designs. Furthermore, since

the ML6426 pin-out is identical for all the options, the filters

can be interchanged. This allows for ease of product migra-

tion to integrate newer resolutions to filter and drive various

DAC outputs at different sampling frequencies.

Table 3. Choosing the Correct Reconstruction Filter and Video Amplifier for TV Applications, ML6426 options

N/A = not available

640

480

VGA

60Hz

31.5kHz

25.175MHz

12.5MHz

ML6426-2

VGA

72Hz

37.9kHz

31.5MHz

15.5MHz

ML6426-3

VGA

75Hz

37.5kHz

31.5MHz

15.5MHz

ML6426-3

800

600

SVGA

56Hz

35.1kHz

36MHz

18MHz

ML6426-3

SVGA

60Hz

37.9kHz

40MHz

20MHz

ML6426-3

SVGA

72Hz

48.1kHz

50MHz

25MHz

ML6426-3

SVGA

75Hz

46.9kHz

49.5MHz

25MHz

ML6426-3

1024

768

XGA

43Hz

Interlaced

35.5kHz

44.9MHz

23MHz

ML6426-3

XGA

60Hz

37.9kHz

65MHz

33MHz

ML6426-5

XGA

70Hz

56.5kHz

75MHz

37.5MHz

ML6426-5

1280

1024

SXGA

75Hz

80kHz

135MHz

68MHz

na

SXGA

60Hz

113MHz

57MHz

na

1600

1200

UXGA

60Hz

166MHz

83MHz

na