LM2470 Monolithic Triple 7.0ns CRT Driver IC

The LM2470 is a high-voltage integrated CRT driver circuit intended specifically for colour monitor applications. The IC is made up of three wide band amplifiers with high input impedance that drive the RGB cathodes of a CRT directly. Each channel’s gain is internally set at 27, allowing it to drive CRT capacitive loads as well as resistive loads supplied by other applications, with the package’s power dissipation being the sole constraint. The IC is housed in a 9-lead TO-220 moulded plastic power package, which is industry standard. The LM2470 is a three-channel high-voltage monolithic CRT driver designed for high-resolution display applications. Power supply of 85V and 8V are compatible with the LM2470.

The LM2470 has a wide bandwidth amplifier function that necessitates correct power supply bypassing for optimal operation. Large overshoot, ringing, and oscillation can occur if the power source is bypassed improperly. Internal arcing can happen on a CRT during regular operation. The maximum voltage will be limited by spark gaps of 200V–300V at the cathodes, but only to a value that is significantly higher than the LM2406 allows. The LM2406, on the other hand, cannot be utilised without a heat sink. This is because when the input signal rises, the power supply current increases, and as a result, power dissipation increases.

Applications

• 1024 x 768 displays up to 85 Hz refresh
• Pixel clock frequencies up to 95 MHz
• Monitors using video blanking