WLED Drivers Encourage Compact Designs

The MAX8901A and MAX8901B, thought to be the industry's smallest, highest efficiency white-LED (WLED) drivers, achieve efficiencies up to 92% while driving a string of two to six WLEDs. They operate at a fixed switching frequency of 750 kHz, accommodating the use of 1-µF input and 0.1-µF output capacitors, and provide a single input to enable the IC and control LED intensity. With LED current proportional to the PWM duty cycle, the MAX8901A employs a direct PWM input to regulate LED intensity, while the MAX8901B relies on single-wire, serial-pulse dimming that reduces LED intensity in 32 linear steps. Serial-pulse dimming current is 24.75 mA, and each increment is 0.75 mA. Both drivers also include internal soft-start, input over-voltage protection, LED over-voltage protection, under-voltage lockout, and thermal shutdown. Power consumption is 0.1 µA in shutdown mode. Available in 8-pin, 2 mm x 2 mm TDFN packages with an operating temperature range from -40°C to +85°C, prices start at $1.25 each/1,000. MAXIM INTEGRATED PRODUCTS, Sunnyvale, CA. (800) 998-8800.