The TPS61290x provides a power supply design for products powered by a nickel-rich, silicon anode, Li-ion, or LiFePO4 battery. The voltage range is optimized for single-cell portable applications like in smart-phones or POS terminal. Used as a high-power pre-regulator, the device extends the battery run-time and overcomes input current and voltage limitations of the powered system. With a wide input voltage range of 1.8V to 5.5V. Program the output voltage by I2C up to 5.5V. The default output voltage of TPS61290 is 3.4V. The default output voltage of TPS612901 is 5V (VSEL = Low) and 5.25V (VSEL = High). During operation, when the battery is in a good state of charge, the TPS61290x works in bypass mode, connecting the battery to the power supply system through the bypass FET. If the battery gets to a lower state of charge and the voltage becomes lower than the desired minimum system voltage, the device seamlessly transits into boost mode to use the full battery capacity. The TPS61290x offers a very small design size with a 16-ball YBG package.