LM1203 National Semiconductor, LM1203 Datasheet - Page 11

• Manufacturer Part Number: LM1203
• Description: RGB Video Amplifier System
• Manufacturer: National Semiconductor

Figure 9 shows how the LM1203 can be set up as a video
Additional Applications of the LM1203
buffer which could be used in low cost video switcher appli-
cations Pin 14 is tied high to turn off the clamp compara-
tors The comparator input pins should be grounded as
shown Sync tip (black level if sync is not included) clamping
is provided by diodes at the amplifier inputs Note that the
clamp cap pins are tied to the Pin 11 2 4V reference This
was done along with the choice of 200
resistor to establish an optimum DC output voltage The
FIGURE 9 RGB Video Buffer with Diode Sync Tip Clamps and 75
for the drive pin
11
contrast control (Pin 12) will provide the necessary gain or
attenuation required for channel balancing Changing the
contrast control setting will cause minor DC shifts at the
amplifier output which will not be objectionable as the out-
put is AC coupled to the load The dual NPN PNP emitter
follower will provide a low impedance output drive to the AC
coupled 75
500
approximately 4 Hz
F capacitors will set the low frequency response to
output impedance setting resistor The dual
Cable Driver
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