Linear Technology LT1931AIS5 - High Efficiency, Low Noise 1.2MHz Step-Up DC/DC Converter

The LT1931AIS5 from Linear Technology is a highly efficient, fixed frequency, step-up DC/DC converter designed to operate as a constant current LED driver for up to six white LEDs. Packaged in a compact SOT-23, this device is perfect for space-constrained applications, offering a high switching frequency of 1.2MHz that allows the use of tiny, low-cost capacitors and inductors 2.2μH in size.

With a wide input voltage range of 2.6V to 16V, the LT1931AIS5 is versatile enough to be powered from a single Li-Ion cell, multiple alkaline/NiMH cells, or a fixed input voltage source. This flexibility makes it suitable for diverse applications, including handheld devices, digital cameras, and other portable products where efficient power conversion is critical.

The LT1931AIS5 boasts an impressive efficiency level of up to 86%, which is achieved through its low V<sub>CESAT switch, 0.4Ω, and 1A current limit. In addition, the device features a unique control scheme that allows it to maintain high efficiency over a wide range of output currents. This makes the LT1931AIS5 an ideal choice for applications requiring extended battery life.

For noise-sensitive applications, the LT1931AIS5's low noise operation is a significant advantage. The switching frequency is set internally at 1.2MHz, allowing the use of small surface mount inductors and capacitors to minimize noise and EMI. Furthermore, its SHDN pin can be used to turn the device off and reduce quiescent current to less than 1μA, further conserving battery life when the converter is not in use.

Additional features of the LT1931AIS5 include a soft-start function that limits inrush current during startup, and a feedback voltage of 1.23V that enables the user to set the output voltage with a single external resistor. This high level of integration ensures a minimal external component count and simplifies the design process, making the LT1931AIS5 a highly effective solution for compact, efficient, and reliable power conversion applications.

Overall, the LT1931AIS5 by Linear Technology is a robust, high-performance step-up converter that delivers low noise, high efficiency, and ease of use, making it an excellent choice for designers looking to enhance the performance of their power-sensitive applications.