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.
The LT3593 is a step‑up DC/DC converter designed to drive up to ten white LEDs in series from a Li‑ion cell. It features a high‑side LED current sense, one‑wire current programming via the CTRL pin, and an output disconnect that turns off the LEDs in shutdown. The device operates at a fixed 1 MHz switching frequency, allowing very small external components.
Typical applications include cell phones, digital cameras, PDAs, MP3 players and GPS receivers. The part is offered in a 6‑lead DFN (2 mm × 2 mm) and a 6‑lead SOT‑23 package, and it supports a wide input voltage range of 2.7 V to 5.5 V with low shutdown current.
| Input Voltage Range | 2.7 V to 5.5 V |
|---|---|
| Switching Frequency | 1 MHz |
| Low Shutdown Current | 3 A |
Use only X5R or X7R ceramic capacitors for the input and output because they retain capacitance over a wide voltage and temperature range.
A 10 µH inductor, such as the Murata LOH43CN100, is recommended for most LT3593 designs.