Maxim Introduces New High Efficiency WLED Drivers

Maxim Integrated Products introduced the MAX8901A/MAX8901B, which the company claims are the industry’s smallest, highest efficiency white-LED (WLED) drivers. These devices achieve up to 92% efficiency while driving a string of 2 to 6 WLEDs.

These 2mm x 2mm devices also feature what the company claims is the industry’s smallest solution size. This is because they operate from a fixed 750kHz (typ) switching frequency, which enables the use of 1µF input and 0.1µF output capacitors. Designed to drive 2 to 6 WLEDs for backlighting, the MAX8901A/MAX8901B are suitable for the 1.5 to 4" LCDs used in battery-operated devices such as smartphones, PDAs, portable media players, GPS devices, and digital still cameras.

The MAX8901A/MAX8901B 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 24.75mA, and each step is 0.75mA. In addition to providing flexible dimming control, the MAX8901A/MAX8901B integrate robust protection features: internal soft-start to eliminate inrush currents during startup, input overvoltage protection, LED overvoltage protection, undervoltage lockout, and thermal shutdown. To conserve battery power, these WLED drivers consume only 0.1µA (typ) in shutdown mode.

The MAX8901A/MAX8901B are available in a thermally enhanced, 2mm x 2mm, 8-pin TDFN package that is fully specified over the -40 to +85°C extended temperature range. Prices start at $1.25 (1000-up, FOB USA).