1MHz White LED Driver with Output Disconnect and One Pin Current Programming

The LT3593 is a step-up DC/DC converter designed to drive up to ten white LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED currents and eliminates the need for ballast resistors. The device features a unique high side LED current sense that enables the part to function as a “one wire current source” where the low side of the LED string can be returned to ground anywhere.

Additional features include output disconnect in shutdown, open LED protection and 1-pin shutdown/LED current control. The CTRL pin is toggled to adjust the LED current via an internal counter and a 5-bit DAC.

The LT3593 switches at 1MHz, allowing the use of tiny external components. Constant frequency switching results in low input noise and a small output capacitor. The LT3593 is available in the 6-lead DFN (2mm × 2mm) as well as the 6-lead SOT-23 packages.

Applications

* Cell Phones

* Digital Cameras

* PDAs, Handheld Computers

* MP3 Players

* GPS Receivers

* Drives Up to Ten White LEDs from a 3V Supply

* One Pin Shutdown and Current Programming

* LEDs Disconnected in Shutdown

* 32:1 Linear Brightness Control Range

* VIN Range: 2.7V to 5.5V

* ±5% Output Current Accuracy at Full Scale

* Low Shutdown Current: 3μA

* 1MHz Switching Frequency

* Requires Only 1μF Output Capacitor

* Low Profile 6-Lead DFN (2mm × 2mm × 0.75mm) and 6-Lead SOT-23 Packages