DC-DC converter with dual-input control enables multi-inputs and extended run times

The LTC3118 is a new dual-input, wide voltage range synchronous buck-boost DC-DC converter, from Linear Technology, featuring an intelligent, integrated low loss PowerPath control. The device's novel power switch architecture provides high efficiency operation from either input source to a programmable output voltage above, below or equal to the inputs. Its dual input capability makes it ideal for applications that use batteries or supercaps as secondary or backup inputs, in case the primary input is interrupted. Similarly, applications that use multiple sources such as a wall adapter and Li-Ion cells could utilize the dual input and buck-boost capability of the LTC3118. The LTC3118 can deliver up to 2A of continuous output current from a wide range of power sources, including single or multiple cell batteries, supercapacitor stacks and wall adapters. Its 2.2V to 18V input range on both inputs and 2.0V to 18V output range can provide a regulated output with inputs above, below or equal to the regulated output. The LTC3118 uses a low noise, current mode buck-boost topology architecture with a fixed 1.2MHz switching frequency. Its unique design provides a continuous, jitter-free transition between buck and boost modes, making it ideal for RF and other noise-sensitive applications. The LTC3118’s integrated low loss PowerPath controller is user programmable to prioritize and seamlessly transition between inputs while maintaining output voltage regulation. The combination of tiny externals and a 4mm x 5mm QFN or TSSOP-28E package provides a compact solution footprint. The LTC3118 includes four internal low RDS(ON) N-channel MOSFETs to deliver efficiencies of up to 94%. User-selectable Burst Mode operation lowers input quiescent current to only 50µA, improving light load efficiency and extending battery run time. For noise-sensitive applications, Burst Mode operation can be disabled. Other features include soft-start, overvoltage protection, short-circuit protection, thermal shutdown and output disconnect. LTC3118EUFD is available in a 24-lead 4mm x 5mm QFN package and the LTC3118EFE is offered in a thermally-enhanced 28-lead TSSOP package. Industrial grade versions operate over the -40C to 125C junction temperature range. High-temperature versions, the LTC3118HUFD and LTC3118HFE, operate over the -40C to 150C junction temperature range. High-reliability defence plastic grades, the LTC3118MPUFD and LTC3118MPFE, operate over the -55C to 150C junction temperature range. All versions are available from stock, says the company.