ML6426
TYPICAL APPLICATIONS
(Continued)
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 individually 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. Micro Linears 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
migration to integrate newer resolutions to filter and drive
various DAC outputs at different sampling frequencies.
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 summarized 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 resolutions for legacy video, SDTV, and
HDTV.
RECONSTRUCTION
FILTER CUTOFF
HORIZONTAL RATE
REFRESH RATE
(prog except noted)
VERTICAL LINES
SAMPLE CLOCK
PIXELS
640
480
800
600
1024
768
VGA
VGA
VGA
SVGA
SVGA
SVGA
SVGA
XGA
XGA
XGA
XGA
SXGA
SXGA
UXGA
1280
1600
N/A = not available
1024
1200
60Hz
72Hz
75Hz
56Hz
60Hz
72Hz
75Hz
43Hz
Interlaced
60Hz
70Hz
75Hz
75Hz
60Hz
60Hz
31.5kHz
37.9kHz
37.5kHz
35.1kHz
37.9kHz
48.1kHz
46.9kHz
35.5kHz
37.9kHz
56.5kHz
60kHz
80kHz
25.175MHz
31.5MHz
31.5MHz
36MHz
40MHz
50MHz
49.5MHz
44.9MHz
65MHz
75MHz
78.75MHz
135MHz
113MHz
166MHz
12.5MHz
15.5MHz
15.5MHz
18MHz
20MHz
25MHz
25MHz
23MHz
33MHz
37.5MHz
39.4MHz
68MHz
57MHz
83MHz
ML6426-2
ML6426-3
ML6426-3
ML6426-3
ML6426-3
ML6426-3
ML6426-3
ML6426-3
ML6426-5
ML6426-5
ML6426-6
na
na
na
Table 3: Choosing the Correct Reconstruction Filter and Video Amplifier for TV Applications, ML6426 options
8
November, 1999
MICRO LINEAR
FILTER TO USE
NAME
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
