LM1276AAA National Semiconductor, LM1276AAA Datasheet - Page 13

• Manufacturer Part Number: LM1276AAA
• Description: 150 MHz I2C Compatible RGB Preamplifier with Internal 512 Character OSD ROM, 512 Character RAM and 4 DACs
• Manufacturer: National Semiconductor

Pin
No.
Typical Performance Characteristics
Pin Descriptions and Application Information
1
2
4
3
5
6
7
8
9
PLL Auto
Analog Ground
Green Video In
Blue Video In
Red Video In
PLL Ground
Analog V
Pin Name
V
PLL Filter
V Sync
REF
R
EXT
CC
25 - 61
PPL=0
25 - 53
PPL=1
TABLE 2. OSD Register Recommendations
25 - 98
PPL=2
Schematic
25 - 110
PPL=3
V
13
CC
= 5V, T
25 - 110
PPL=4
A
= 25˚C unless otherwise specified (Continued)
Logic level vertical sync signal received from the
video card in the PC or sync stripper circuit.
Ground pin and power supply pin for the input
analog portion of the LM1276. Note the
recommended charge storage and high
frequency capacitors, which should be as close
to pins 2 and 4 as possible.
External current set resistor, 10k 1%, sets the
internal bias current level for optimum
performance of the LM1276. This resistor should
be placed as close to pin 3 and the pin 4 ground
return as possible.
These video inputs must be AC coupled with a
.0047 µF cap. Internal DC restoration is done at
these inputs. A series resistor of about 33Ω and
external ESD protection diodes should also be
used for protection from ESD damage.
Recommended topology and values are shown
to the left. It is recommended that both filter
branches be bypassed to the independent
ground as close to pin 8 as possible. Great care
should be taken to prevent external signals from
coupling into this filter from video, I
25 - 108
PPL=5
Description
25 - 102
PPL=6
2
C, etc.
www.national.com
25 - 96
PPL=7