20mA LED Driver and OLED Driver with Integrated Schottky in 3mm x 2mm DFN

The LT3498 is a dual output boost converter featuring a 2.3MHz PWM LED Driver and PFM OLED Driver. It includes an internal power switch and Schottky diode for each driver. Both converters can be independently shut down and modulated. This highly integrated power solution is ideal for dual display electronic devices.

The 2.3MHz step-up converter is designed to drive up to six white LEDs in series from a Li-Ion cell. The device features a unique high side LED current sense that enables the part to function as a “one-wire” current source—one side of the LED string can be returned to ground anywhere. Traditional LED drivers use a grounded resistor to sense LED current, requiring a 2-wire connection to the LED string.

The PFM OLED driver is a low noise boost converter that features a novel control technique.* The converter controls power delivery by varying both the peak inductor current and switch off time. This technique results in low output voltage ripple, as well as, high efficiency over a wide load range. The off time of the switch is not allowed to exceed a fixed level, guaranteeing a switching frequency that stays above the audio band.

Applications

* Cellular Phones

* PDAs, Handheld Computers

* Digital Cameras

* MP3 Players

* GPS Receivers

* Dual Output Boost for Dual Display Devices

* Drives Up to Six White LEDs and OLED/LCD Bias

* Internal Power Switches and Schottky Diodes

* Independent Dimming and Shutdown

* 200mV High Side Sense on LED Driver Allows "One-Wire Current Source"

* Wide Input Voltage Range: 2.5V to 12V

* Wide Output Voltage Range: Up to 32V

* 2.3MHz PWM Frequency for LED Driver

* PFM for OLED Driver is Non-Audible Over Entire Load Range

* Open LED Protection (27V Maximum on CAP1 Pin)

* OLED Output Disconnect

* Available in 12-Pin DFN Package

* 1mm Tall Solution Height