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.