400mA Synchronous Step-Up dc/dc Converter

Linear Technology's LTC3105, a high performance, synchronous boost converter incorporates maximum power point control (MPPC) and starts up with inputs as low as 250mV. The LTC3105 operates over an input range of 0.2 to 5V, making it useful for harvesting energy from high impedance alternative power sources, including photovoltaic cells, thermoelectric generators (TEGs) and fuel cells. The LTC3105's internal 400mA synchronous switches maximize efficiency while its Burst Mode^® operation offers quiescent current of only 22uA, further optimizing converter efficiency overall operating conditions. A user-programmable MPPC set point maximizes the energy that can be extracted from any power source without collapsing its internal voltage.

The LTC3105 is useful to power wireless sensors and data acquisition applications. Surplus or ambient energy can be harvested and then used to generate system power in lieu of traditional wired or battery power, which may be expensive or impractical. Typically, these applications require very low average power, but require periodic pulses of higher load current. For example, the LTC3105 can be used in wireless sensor applications where the power load is extremely low when the sensor is in standby mode, interrupted by periodic high load bursts, when the circuitry is powered up to take measurements and transmit data.
The LTC3105 offers an auxiliary LDO that delivers up to 6mA of output current to power external microcontrollers and sensors while the main output is charging. Once fully charged, the main output can deliver voltages as high as 5.25V with up to 100mA of output current. It can also regulate VOUT even when V_IN is greater than or equal to V_OUT, offering further design flexibility. In shutdown, the LTC3105 offers output disconnect, isolating V_IN from V_OUT, requiring only 4uA of quiescent current.

The LTC3105EDD is available in a 10-lead 3 x 3mm DFN package and the LTC3105EMS is available in an MSOP-12 package. Prices start at $2.70 each for 1,000-piece quantities. Both are available from stock.