MAX1698

19-1621; Rev 0; 1/00 KIT ATION EVALU E L B A IL AVA High-Efficiency Step-Up Current Regulator for LEDs Features o Over 90% Efficiency o Lossless, Adjustable LED Brightness o Space-Saving 10-Pin µMAX Package o Simpler, Lower Cost, More Reliable Compared to CCFL or EL Backlights o Up to 5W Output Power General Description The MAX1698 is the most efficient driver for white or color LEDs. The device is ideal for LED backlit displays in PDAs and digital cameras, and can also be used for larger displays like those in laptop computers. Its numerous benefits include greater simplicity, lower cost, higher efficiency, longer bulb life, and greater reliability when compared to fluorescent (CCFL) and electroluminescent (EL) lamps. The MAX1698 is a switch-mode boost controller in which LED current, rather than output voltage, provides the feedback signal. It can operate with battery inputs as low as 0.8V. The device drives series-connected LEDs with a controlled current that is measured at a sense resistor connected at the feedback pin. The required sense resistor is typically 15Ω, not an expensive fractional-ohm value. LED current control and dimming are accomplished with an adjust input (ADJ), not with lossy current-limiting resistors. For larger light output, multiple LED banks can be connected in parallel with up to 5W total output power. The MAX1698 is supplied in a space-saving 10-pin µMAX package that occupies half the space of an 8-pin SO. An evaluation kit (MAX1698EVKIT) is av...