Buck-Boost DC-DC Converter

Linear Technology Corp.’s LTC3441 is a synchronous, fixed frequency buck-boost dc-dc converter that can deliver up to 1A amp of output current at efficiencies as high as 95%. The LTC3441 is designed to optimize battery run time for single cell Li-Ion, multicell alkaline or NiMH battery-powered applications. It operates from an input voltage range of 2.4V to 5.5V and can provide up to 1A of output current at a fixed output voltage between 2.4V to 5.25V.

A unique buck-boost topology allows the LTC3441 to operate above, below, and equal to the output voltage with a single inductor, providing a continuous transfer function through all the operating modes, as the battery voltage declines. The operating frequency is set internally to 1 MHz and can be synchronized up to 2 MHz, allowing the use of tiny surface-mount components and maintaining the switching noise well above the pass-band of most communication systems. The small implementation footprint makes it ideal for space-constrained environments such as cellular phones, PDAs, wireless and DSL modems and digital cameras.

The LTC3441 uses two 0.10Ω N-channel and two 0.11Ω P-channel switches in a constant frequency, synchronous switching topology to obtain efficiencies as high as 95%. Its selectable Burst Mode® operation allows the internal power MOSFETs to operate intermittently based on load demand and reduces the quiescent current to a low 25uA when there is no load (less than 1uA in shutdown). Furthermore, the selectable Burst Mode operation is inhibited during synchronization or when the SYNC/MODE pin is pulled low, preventing low frequency ripple from interfering with audio circuitry. The LTC3441 also features anti-ringing control to minimize EMI, soft-start control and thermal shutdown.

For more information, visit www.linear.com.