Video Amplifier System - Mitsubishi DPLUS 74SB -BKA Service Manual

7. Video amplifier system

LM1269
110 MHz I²C RGB Video Amplifier System with OSD & DACs
General Description
The LM1269 pre-amp is an integrated CMOS CRT pre-amp. The IC is I2C compatible, and allows
control of all the parameters necessary to direct setup and adjust the gain and contrast in the CRT
display. Brightness and bias can be controlled through the DAC outputs, and is well matched to the
LM2479 and LM2480 integrated bias clamp IC.
The LM1269 pre-amp is designed to work in cooperation with the LM246X high gain driver family.
Black level clamping of the signal is carried out directly on the AC coupled input signal into the high
impedance preamplifier input, thus eliminating the need for the additional black level clamp capaci-
tors.
The IC is packaged in an industry standard 24-lead DIP molded plastic package.
Features
• I
C compatible interface to micro-controller
2
• 110 MHz bandwidth preamplifier with full video signal parametric control
• 4 external 8-bit DACs for bus controlled Bias and Brightness
• Suitable for use with discrete or integrated clamp, with software configurable Brightness mixer
• Power Save (Green) Mode, 80% power reduction
• Matched to LM246X driver
Applications
• Low end 14", 15", and 17" bus controlled monitors with OSD
• 1024 X 768 displays up to 70 Hz requiring OSD capability
• Very low cost system with LM246X driver
Block and Connection Diagram
Timing Diagrams
7-36