Sunnyvale, Calif. Maxim Integrated Products has introduced high-efficiency white LED (WLED) drivers that achieve up to 92% efficiency while driving a string of two to six white LEDs. The MAX8901A/MAX8901B drivers, packaged in a 2 x 2-mm TDFN, operate from a fixed 750 kHz (typ) switching frequency, enabling the use of 1 microfarad input and 0.1 microfarad output capacitors.
Designed to drive two to six WLEDs for backlighting, the MAX8901A/MAX8901B step-up DC/DC converters are suitable for the 1.5- to 4-inch LCDs used in battery-operated devices such as smart phones, PDAs, portable media players, GPS devices, and digital still cameras.
The MAX8901A/MAX8901B devices provide a single input to enable the IC and to control LED intensity. With the LED current proportional to the PWM duty cycle, the MAX8901A uses a direct-PWM input to regulate LED intensity. In contrast, the MAX8901B uses single-wire, serial-pulse dimming that reduces LED intensity in 32 linear steps. Full-scale LED current for serial-pulse dimming is 24.75 mA, and 0.75 mA for each step.
In addition to providing flexible dimming control, the MAX8901A/MAX8901B drivers integrate several protection features: internal soft-start to eliminate inrush currents during startup, input over-voltage protection, LED over-voltage protection, under-voltage lockout, and thermal shutdown. To conserve battery power, these WLED drivers consume only 0.1 microamps (typ) in shutdown mode. The devices are specified over the -40°C to 85°C extended temperature range.
Pricing: Starts at $1.25 (1000-up, FOB USA).
Maxim Integrated Products , 1-800-998-8800, www.maxim-ic.com