LM1253A

LM1253A Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator May 2000 LM1253A Monolithic Triple 180 MHz I2C CRT Pre-amp With Integrated Analog On Screen Display (OSD) Generator General Description The LM1253A pre-amp is an integrated high voltage triple CRT pre-amp and Analog On Screen Display (OSD) generator. The IC is I2C controlled, and allows control of all the parameters necessary to setup and adjust the brightness and contrast in the CRT display. In addition, it provides a programmable period vertical blanking pulse which is used to blank the G1. The LM1253A pre-amp is designed to work in cooperation with the LM2453 driver, and provides a multiplexed video signal (VideoPlex) interface to enable the DC clamp levels at the cathode to be varied in order to set up the CRT bias and to allow individual adjustment for brightness. The Analog OSD has a selectable palette allowing a wide selection of colors. The preset level of the OSD can be controlled by I2C to suit different CRT displays. The OSD signal is internally mixed with the video signal, before the gain section, and thus gives excellent white tracking of the OSD with the white color point setting of the video. The Brightness settings are also mixed into the video signal before the gain matching controls and consequently give excellent white color point tracking with variations in the Brightness control. An active horizontal blanking signal is added to the video at the out...