LM1276
150 MHz I2C Compatible RGB Preamplifier with Internal
512 Character OSD ROM, 512 Character RAM and 4
DACs
General Description
The LM1276 pre-amp is an integrated CMOS CRT preamp
with an integrated Hi-Brite Window generator, 512 Character
OSD generator, and an auto size measurement circuit. It has
an I2C compatible interface, which allows control of all the
parameters necessary to directly setup and adjust the gain
and contrast in the CRT display. Brightness and bias can be
controlled through the DAC outputs, which are well matched
to the LM2479 and LM2480 integrated bias clamp ICs. The
LM1276 preamp is also designed to be compatible with the
LM247x high gain driver family.
Black level clamping of the video signal is carried out directly
on the AC coupled input signal into the high impedance
preamplifier input, thus eliminating the need for additional
clamp capacitors. Horizontal and vertical blanking of the
outputs is provided. Vertical blanking is optional and its
duration is register programmable.
The IC is packaged in an industry standard 28-lead narrow
DIP molded plastic package.
Features
n Integrated Hi-Brite Window Generator operation
independent of the Microcontroller.
n Programmable Video Emphasis Control.
n 8 Programmable Hi-Brite Windows.
n Hi-Brite Enhancement on full screen, window only, or
outside of windows.
n Fully addressable 512 Character OSD.
n Internal 512 character OSD ROM usable as either (a)
384 2-color plus 128 4-color characters, (b) 640 2-color
characters, or (c) some combination in between.
n Internal 512 character RAM.