Low-Dropout, Constant-Current Triple White LED Bias Supply

The MAX1916 low-dropout bias supply for white LEDs is a high-performance alternative to the simple ballast resistors used in conventional white LED designs. The MAX1916 uses a single resistor to set the bias current for three LEDs, which are matched to 0.3%. The MAX1916 consumes only 40µA of supply current when enabled and 0.05µA when disabled.

The MAX1916's advantages over ballast resistors include significantly better LED-to-LED bias matching, much lower bias variation with supply voltage variation, significantly lower dropout voltage, and in some applications, significantly improved efficiency. The MAX1916 requires a 200mV dropout at a 9mA load on each output to match the LED brightness.

The MAX1916 is available in a space-saving 6-pin Thin SOT23 package.

Applications

* Battery-Powered Applications * Digital Cameras and Camcorders * Next-Generation Wireless handsets * PDAs, Palmtops, and Handy Terminals

* Low 200mV Dropout at 9mA

* Up to 60mA/LED Bias Current

* 0.3% LED Current Matching

* Simple LED Brightness Control

* Low 40µA Supply Current

* Low 0.05µA Shutdown Current

* 2.5V to 5.5V Supply Voltage Range

* Thermal Shutdown Protection

* Tiny 6-Pin Thin SOT23 Package (1mm High)