LM1247

LM1247 150 MHz I2C Compatible RGB Preamplifier with Internal 512 Character OSD ROM, 512 Character RAM and 4 DACs December 2002 LM1247 150 MHz I2C Compatible RGB Preamplifier with Internal 512 Character OSD ROM, 512 Character RAM and 4 DACs General Description The LM1247 pre-amp is an integrated CMOS CRT preamp. 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 LM1247 preamp is also designed to be compatible with the LM246x 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 24 lead DIP molded plastic package. n I2C compatible microcontroller interface n OSD override allows OSD messages to override video and the use of burn-in screens with no video input n 4 DAC outputs (8-bit resolution) for bus controlled CRT bias and brightness n Spot killer which blanks the video outputs when VCC falls below the specified threshold n Suitable for use with discrete or integrated clamp, with software c...