LM1283

140 MHz RGB Video Amplifier System with On Screen

Display (OSD)

General Description

The LM1283 is a full feature video amplifier with OSD inputs,

all within a 28-pin package. This part is intended for use in

monitors with resolutions up to 1280 x 1024. The video sec-

tion of the LM1283 features three matched video amplifiers

with blanking. All of the video amplifier adjustments feature

high input impedance 0V to 4V DC controls, providing easy

interfacing to bus controlled alignment systems. The OSD

section features three TTL inputs and a DC contrast control.

The switching between the OSD and video section is con-

trolled by a single TTL input. Although the OSD signals are

TTL inputs, these signals are internally processed to match

the OSD logic low level to the video black level. When ad-

justing the drive controls for color balance of the video sig-

nal, the color balance of the OSD display will track these

color adjustments. The LM1283 also features an internal

spot killer circuit to protect the CRT when the monitor is

turned off. For applications without OSD insertion please re-

fer to the LM1205 or LM1208 data sheets.

Features

(4 V

n TTL OSD inputs, 50 MHz bandwidth

n On chip blanking, outputs under 0.1 V when blanked

n Video/OSD switch speed of 7 ns

n Independent drive control for each channel for color

balance

n 0V to 4V, high impedance DC contrast control with over

40 dB range

n 0V to 4V, high impedance DC drive control (0 dB to

−12 dB range)

n 0V to 4V, high impedance DC OSD contrast control with

over 40 dB range

bandwidth)

n Output stage directly drives most hybrid or discrete CRT

drivers

Applications

n High resolution RGB CRT monitors requiring OSD

capability

Block and Connection Diagram

DS012684-1

FIGURE 1. Order Number LM1283N

See NS Package Number N28B

April 1999

© 1999 National Semiconductor Corporation

DS012684

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