MAX8728EVKIT

Product Details

The MAX8728 evaluation kit (EV kit) is a fully assembled and tested surface-mount circuit board that provides the voltages and features required for active-matrix thin-film transistor (TFT), liquid-crystal display (LCD) panels in LCD monitors and LCD TVs. The EV kit contains a stepdown switching regulator, a step-up switching regulator, a positive two-stage charge pump for the TFT gate-on supply, and a negative single-stage charge pump for the TFT gate-off supply. Also included is a logic-controlled, high-voltage switch with adjustable delay, and a capacitive dummy load at the gate-on supply for ease of testing.

The EV kit, as configured, provides the following outputs from a +10VDC to +13.2VDC power supply. The step-down switching regulator is configured for a +3.3V output, providing at least 2A. The step-up switching regulator is configured for a +13.5V output, providing at least 500mA. The positive charge pump is configured for a +28V output, providing at least 50mA. The negative charge pump is configured for a -6V output, providing at least 150mA. The high-voltage switch can be controlled by external logic and can be configured for a delay set by an external capacitor.

The MAX8728 switches at 1.5MHz, allowing the use of tiny surface-mount components. The EV kit can also operate at a lower frequency with component changes. The MAX8728 TQFN package (0.8mm maximum height) with low-profile external components allows this circuit to be less than 2mm high.