Dual output step-down charge pump operates without inductors

August 12, 2016 // By Julien Happich
Linear Technology's LTC3256 is a high voltage low noise dual output power supply, which takes a single positive input and generates 5V and 3.3V step-down supplies with high efficiency and no inductors.

The device features a wide 5.5V to 38V input voltage range and includes independently enabled dual outputs: a 5V 100mA supply, and a 250mA 3.3V low-dropout (LDO) regulator, for a total of 350mA available output current.

This combination of regulators offers much lower power dissipation than a dual-LDO solution. For example at 12V VIN and maximum load on both outputs, power dissipation is decreased by over 2W with the LTC3256, thus reducing significant heat and input current.

The LTC3256 maximizes efficiency by running the charge pump in 2:1 mode, over as wide an operating range as possible, and automatically switches to 1:1 mode as needed, consistent with VIN and load conditions. Controlled input current and soft switching minimize conducted and radiated EMI. The device offers low quiescent current of only 20μA with both outputs regulating (no load) and 0.5μA in shutdown.

The LTC3256 is available in a thermally enhanced 16-lead MSOP package, with a backside thermal pad with rated for operation in the –55°C to 150°C temperature range.

Visit Linear at www.linear.com/product/LTC3256>