Buck-Boost DC/DC uModule Regulator Dissipates Less than 2.4W at 60WOUT without Hot Spots

The LTM4605 integrates a synchronous buck-boost DC/DC controller, four N-channel MOSFETs, input and output bypass capacitors and the compensation circuitry in a 15mm x 15mm x 2.8mm land grid array (LGA) plastic molded package. Only an inductor, feedback and sense resistors and bulk capacitors are required to implement a very low profile, compact and high efficiency design. The LTM4605 provides a compact regulator solution in applications such as networking, industrial and automotive systems and high-power battery operated devices.

With the LTM4605's on-board proprietary 4-switch synchronous MOSFET design, the product achieves up to 97.3% efficiency in boost mode and up to 97.7% efficiency in buck mode (VIN: 4.5V to 20V, VOUT: 12V, IOUT: 5A). Whereas other topologies such as SEPIC (Single Ended Primary Inductor Converter) require as many as 20 components and custom magnetics, this buck-boost uModule solution uses only eight components and an off-the-shelf inductor. In addition, the efficiency of a comparable SEPIC circuit is approximately 76% to 84%. Furthermore, to reduce undesirable frequency harmonics, the LTM4605 is phase-lockable to an external clock frequency ranging from 200kHz to 400kHz. Safety features include overvoltage and foldback current protection.