MAX9540 Maxim Integrated Products, MAX9540 Datasheet - Page 8

• Manufacturer Part Number: MAX9540
• Description: (MAX9539 / MAX9540) Graphics Video Sync Adder/Extractor
• Manufacturer: Maxim Integrated Products

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The MAX9539/MAX9540 chipset provides a 3-wire
(RGB) interface for 5-wire (RGBHV) video by adding
and extracting the H, V, and composite sync from the
graphics video signals. This chipset eliminates the
problem of sync-to-video timing (skew errors) in a 5-
wire interface, while reducing the number of channels
required when transporting video signals.
The MAX9539 mixes the H and V sync signals and
adds them to create a 3-wire interface from a 5-wire
(RGBHV) input. The MAX9540 recovers the H and V
sync signals to create a 5-wire (RGBHV) interface from
the 3-wire input. The MAX9540 also provides a com-
posite sync output.
The chipset includes the MAX9539 sync adder and the
MAX9540 sync extractor with 180MHz large-signal
bandwidths to address display resolutions up to 1600 x
1200 at 85Hz for VGA-to-UXGA applications. Both
devices feature a DC-restore function, which virtually
eliminates any changes in black level. The chipset uses
a proprietary H and V sync addition/extraction scheme
(true sync) to minimize skew errors.
Graphics Video Sync Adder/Extractor
8
4, 9, 10, 14,
15, 20, 25
2, 7, 12
_______________________________________________________________________________________
PIN
11
13
16
17
18
19
21
22
23
24
26
27
28
1
3
5
6
8
REST_G
REST_R
REST_B
CSYNC
OUT_G
HSYNC
VSYNC
OUT_B
OUT_R
NAME
SP_C
SP_H
IN_G
SP_V
IN_R
GND
IN_B
N.C.
V
V
I.C.
CC
EE
Detailed Description
Red Video Input with Horizontal Sync
Ground
Red DC Restore. Connect a 1nF capacitor from REST_R to GND.
No Connection. Not internally connected.
Internally Connected. For best performance, connect this pin to GND.
Green Video Input with Composite Sync
Green DC Restore. Connect a 1nF capacitor from REST_G to GND.
Blue Video Input with Vertical Sync
Blue DC Restore. Connect a 1nF capacitor from REST_B to GND.
Vertical Sync Output
Vertical Sync Polarity Input
Blue Video Output
Negative Power-Supply Input. Bypass with a 0.1µF capacitor to GND.
Composite Sync Output
Composite Sync Polarity Input
Green Video Output
Positive Power-Supply Input. Bypass with a 0.1µF capacitor to GND.
Horizontal Sync Output
Horizontal Sync Polarity Input
Red Video Output
The MAX9539 mixes the H and V sync signals and
adds them to create a 3-wire interface from a 5-wire
(RGBHV) input. Sync signals are added to the input
video signals. Horizontal sync is added to red video,
vertical sync is added to blue video, and composite
sync is added to green video. Composite sync is the
XOR function between H sync and V sync and is inter-
nally generated by the MAX9539. The sync level of the
video outputs is -2.4V. The DC-restore function
removes any DC offset (∆V
video inputs and sets the output black level to 0V at the
back porch of the H sync. Therefore, the output black
level is set to 0V at the beginning of every line.
Figure 2 illustrates the functionality of the MAX9539. In
this example, the sync signals are of positive polarity.
The MAX9540 recovers the H and V sync signals to cre-
ate a 5-wire (RGBHV) interface from the 3-wire input. The
output video signals are obtained by removing the sync
pulses of the input video. The sync outputs correspond
to the sync pulses of the input video: horizontal sync is
FUNCTION
MAX9540 Pin Description
MAX9540 Sync Extractor
MAX9539 Sync Adder
IN_RESTORE
) in the RGB