The LTC3490 is a single-cell 350mA LED driver suitable for portable lighting and rechargeable flashlight applications. It features synchronous rectification technology for efficiency up to 90%, fixed frequency operation at 1.3MHz, low quiescent current of <1mA, very low shutdown current of <50µA, open LED output limited to 4.7V, VIN range of 1V to 3.2V, dimming control, and undervoltage lockout to protect batteries.
The LTC3490 provides a constant‑current drive for 1 W LED applications, delivering up to 350 mA with an output compliance of 2.8 V to 4 V. It operates from a single or dual NiMH or alkaline cell and features synchronous rectification for up to 90 % efficiency.
Key features include a low‑quiescent current (<1 mA), very low shutdown current (<50 µA), analog dimming via the CTRL/SHDN pin, and built‑in undervoltage lockout to protect batteries. The device is supplied in an 8‑lead DFN package with a 1.3 MHz fixed switching frequency.
| Constant Current Output | 350 mA |
|---|---|
| Output Compliance Voltage | 2.8 V to 4 V |
| Input Voltage Range (Vin) | 1 V to 3.2 V |
| Switching Frequency | 1.3 MHz |
| Quiescent Current | <1 mA |
| Shutdown Current | <50 µA |
| Maximum Output Voltage (Open LED) | 4.7 V |
The LTC3490 limits the output voltage to 4.7 V when the LED load is open.
It operates from 1 V up to 3.2 V input voltage.
The shutdown current is less than 50 µA.
The device uses a fixed switching frequency of 1.3 MHz.