LM1253A National Semiconductor, LM1253A Datasheet - Page 15

• Manufacturer Part Number: LM1253A
• Description: Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator
• Manufacturer: National Semiconductor

Input/Output Schematics
National VideoPlex Video System
The LM1253A CRT Pre-Amp in conjunction with the LM2453
CRT driver uses the National VideoPlex multiplexed video
The response of the LM2453 CRT driver to the VideoPlex
signal from the LM1253A Pre-Amp is shown in Figure 24 .
Note that there are two sections in the video signal; the video
information is above V
REF
and the clamp information is be-
FIGURE 23. National VideoPlex Video Signal (Pre-Amp Output)
FIGURE 21. Pins 23, 24, and 25 (Video Out)
(Continued)
FIGURE 22. Pin 26 V
15
signal to send the video signal and DC clamp level from the
pre-amp to the CRT driver. The basic signal scheme is
shown in Figure 23 .
low V
LM2453 for an arbitrary video waveform from the LM1253A
is shown in Figure 25 .
REF
REF
Out
. The signals on the video out and clamp pins of the
DS101265-25
DS101265-24
DS101265-26
www.national.com