The MAX20343/MAX20344 is an ultra-low quiescent current, noninverting buck-boost converter with 1A current capability at 3.5V intended for applications that require long run times while also demanding bursts of high current. The device employs a unique control algorithm which seamlessly transitions between buck, buck-boost, and boost modes, minimizing discontinuities and subharmonics in the output voltage ripple. The low 1.9V input voltage for startup allows users to power the device from a variety of sources, and the near-zero minimum operating voltage gives the user the ability to extract as much as possible from their energy source. The MAX20343/MAX20344 has also been designed to keep inductance and output capacitance requirements as low as possible for space-constrained applications.The MAX20343/MAX20344 is ideal for power in optical sensor applications as well as for powering radios in low power, wide area network (LPWAN) applications since in both cases noise must be minimal and efficiency must be high. For instance, the small light-load output voltage ripple allows a photoplethysmography (PPG) system to operate at low LED currents without interference. Additionally, seamless transitions between operating modes enables the use of dynamic voltage scaling (DVS) to minimize headroom on the LED and to save power in such systems. In applications where a low-power-density battery must be buffered by a super-capacitor to provide large LPWAN type bursts of current, the ultra-low operating voltage of the MAX20343/MAX20344 allows the user to extract as much energy as possible from the super capacitor. The low output inductance/capacitance requirement allows a small total solution size. For example in PPG systems, this provides the flexibility to place the MAX20343/MAX20344 on a remote optical module if overcrowding on the main PCB is an issue.The MAX20343/MAX20344 is available with a highly configurable I2C serial interface or as a single-pin-enabled fixed-programming version. See Table 3 for specific device settings. MAX20343 operates over the -40°C to +85°C temperature range, is available in a 16-bump, 1.77mm x 2.01mm, 0.4mm pitch WLP package and a 12-pin, 2.50mm x 2.50mm, 0.5mm pitch FC2QFN package. MAX20344 operates over the -40°C to +125°C temperature range, and is available in a 12-pin, 2.50mm x 2.50mm, 0.5mm pitch FC2QFN package.ApplicationsBiometric Optical Sensing Including PPGIndustrial SensorsIoTLPWAN (LTE/NB-IoT, LTE/Cat-M1)