18V, 5A buck-boost DC/DC delivers 95% efficiency

18V, 5A buck-boost DC/DC delivers 95% efficiency

New Products |
By Graham Prophet

The device’s 2.5V to 18V input voltage range extends down to 250 mV once started. The output voltage is regulated with inputs above, below or equal to the output and is programmable from 0.8V to 18V. User-selectable Burst Mode operation lowers quiescent current to 35 µA, improving light load efficiency and extending battery run time. The 4-switch PWM buck-boost topology incorporated in the LTC3119 provides low noise, jitter-free switching through all operating modes, for RF and precision analogue applications that are sensitive to power supply noise. The device also includes programmable maximum power point control (MPPC) capability, ensuring maximum power delivery from power sources with high output impedance or photovoltaic cells.


The LTC3119 includes four internal low RDS(ON) N-channel MOSFETs to deliver efficiencies of up to 95%. Burst Mode operation can be disabled, offering low noise continuous switching. External frequency programming or synchronization using an internal PLL enables operation over a wide switching frequency range of 400 kHz to 2 MHz, which allows for a tradeoff between efficiency and solution size. Other features include short-circuit protection, thermal overload protection, less than 3 µA shutdown current, and a power-good indicator. The device is suited for RF power supplies, high current pulsed load applications, system backup power supplies, and lead-acid battery to 12V conversion systems.


LTC3119 is available in thermally enhanced 28-lead 4 x 5 mm QFN and 28-lead TSSOP packages. E- and I-grade devices are specified over the –40°C to 125°C operating temperature range, H-grade from –40°C to 150°C, and MP-grade from –55°C to 150°C. E-grade pricing starts at $7.15 (1,000).


Linear Technology;


next page; feature list…

Summary of Features: LTC3119


Input voltage range: 2.5V to 18V

Runs down to VIN = 250 mV after start-up

Output voltage range: 0.8V to 18V

5A output current in buck mode, VIN > 6V

3A output current for VIN = 3.6V, VOUT = 5V

Programmable switching frequency: 400 kHz to 2 MHz

Synchronizable with an external clock up to 2 MHz

Accurate run comparator threshold

Burst Mode® operation, no-load IQ = 35 µA

Ultralow noise buck-boost PWM

Current mode control

Maximum power point control

Power good indicator

Internal soft-start

28-lead 4 × 5 mm QFN and 28-lead TSSOP packages


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