18V buck-boost DC/DC converter delivers 95% efficiency

The LTC3119, a synchronous current mode monolithic buck-boost converter, from Linear Technology is said to deliver up to 5A of continuous output current in buck mode from a variety of input sources, including single- or multiple-cell batteries, unregulated wall adaptors as well as solar panels and supercapacitors.

The device’s 2.5V to 18V input voltage range extends to 250mV once started. The output voltage is programmable from 0.8V to 18V. Burst Mode operation lowers quiescent current to 35µA, which is claimed to improve light load efficiency while extending battery run time. It can also be disabled, offering low noise continuous switching.

According to the company, the 4-switch pulse-width modulation topology incorporated in the LTC3119 provides low noise, jitter-free switching through all operating modes. The device is also said to include programmable maximum power point control capability, ensuring maximum power delivery from power sources with high output impedance or photovoltaic cells.

Including four internal low RDSON N-channel MOSFETs, the LTC3119 is claimed to deliver efficiencies of up to 95%. External frequency programming or synchronisation using an internal PLL enables operation over a switching frequency range of 400kHz to 2MHz. Other features include short-circuit protection, thermal overload protection and less than 3µA shutdown current.

Applications include RF power supplies, high current pulsed load applications, system backup power supplies, and lead-acid battery to 12V conversion systems.

The LTC3119 is available in thermally enhanced 28-lead 4 x 5mm QFN and 28-lead TSSOP packages. E- and I-grade devices are specified over temperatures ranging from –40 to 125°C, H-grade from –40 to 150°C, and MP-grade from –55 to 150°C.

Peggy Lee