DESCRIPTION
The SS6652 is a high-performance inverting DC/DC controller, designed to drive an external power switch to generate programmable negative voltages, and is particularly suited to LCD bias contrast applications. Efficiency of 87% can be achieved with low cost PNP bipolar transistor drivers. Output voltage can be scaled to -40V or greater by two external resistors. A pulse frequency modulation scheme is employed to maintain high-efficiency conversion over a wide input voltage range. Quiescent current is about 80mA and can be reduced to 0.7mA in shutdown mode. With switching frequencies in the 70KHz to 160KHz range, the small size switching components are ideal for battery powered portable equipment, like notebook and palmtop computers.

FEATURES
 • 2.4V to 7V input voltage operation.
 • Adjustable output voltage up to -40V.
 • Low quiescent current at 80mA.
 • Pulse frequency modulation maintains high efficiency (87%).
 • 70KHz to 160KHz switching frequency.
 • Power-saving shutdown mode (0.7mA typical).
 • High efficiency with low cost external P-channel MOSFET or PNP bipolar transistor.

APPLICATIONS
 • Negative LCD Contrast Bias for
    1. Notebook & Palmtop Computers.
    2. Pen-Based Data System.
    3. Portable Data Collection Terminals.
    4. Personal Digital Assistants.
 • Negative Voltage Supply.