MAX749CSA+T

The MAX749CSA+T is a digitally adjustable LCD bias supply in 8 pin NSOIC package. It generates negative LCD bias contrast voltages from 2V to 6V inputs. Full-scale output voltage can be scaled to -100V or greater and is digitally adjustable in 64 equal steps by an internal digital to analogue converter (DAC). Only seven small surface mount components are required to build a complete supply. The output voltage can also be adjusted using a PWM signal or a potentiometer. A unique current limited control scheme reduces supply current and maximizes efficiency while a high switching frequency (up to 500KHz) minimizes size of external components. Quiescent current is only 60µA max and is reduced to under 15µA in shutdown mode. While shut down, IC retains voltage set point, simplifying software control. It drives either an external P-channel MOSFET or a PNP transistor. It is used in notebook, laptop & palmtop computers, personal digital assistants & communicating computers.