LM2453

The LM2453 driver is an integrated high voltage triple CRT driver circuit designed for use in color monitor applications. The input signal interface to the IC is a multiplexed signal containing both clamp and video signal information, relative to a 1.7 VDC reference.

The LM2453 contains three high gain, high input impedance, wide band amplifiers which directly drive the RGB cathodes of a CRT. Each channel has its gain internally set to −52 and can drive CRT capacitive loads as well as resistive loads present in other applications, limited only by the package's power dissipation.

Integrated with the driver is triple clamp circuit for DC recovery of each of the AC coupled outputs. The DC clamp circuit amplifies the clamp signal that is multiplexed on the video signal input. The DC clamp amplifiers are high gain, high input impedance amplifiers, setting a low impedance DC level at the clamp output which can be used to restore the DC level of the cathode drive. Each channel has a gain that is internally set to +73.

Also integrated within the package is a 40 VP-P vertical blanking driver that is designed to provide vertical retrace blanking on G1 of the CRT. This is a current limited, low impedance output capable of driving normal G1 decoupling capacitances via an external resistor. The output of the G1 driver can also be used to drive a voltage boost capacitor (22 F). When connected between the G1 drive output and the 120V supply input pin, a 120V boost supply is achieved which can be used to drive the internal DC clamp circuit, thereby eliminating the requirement for a 120V clamp supply.
The IC is packaged in an industry standard 15-lead TO-220 molded plastic power package.