The TC125/126 step-up (Boost) switching regulators furnish output currents to a maximum of 80 mA (VIN = 2V, VOUT = 3V) with typical efficiencies above 80%. These devices employ pulse frequency modulation (PFM) for minimum supply current at low loads. They are ideal for battery-operated applications powered from one or more cells. Maximum supply current is less than 70 μA at full output load, and less than 5 μA in standby (VOUT = 3V). Both devices require only an external inductor, diode, and capacitor to implement a complete DC/DC regulator. The TC126 has separate output voltage sensing and chip power inputs for greater application flexibility. The TC125 combines the output voltage sensing and chip power inputs onto a single package pin, but adds a power-saving Shutdown mode that suspends regulator operation and reduces supply current to less than 0.5 μA when the shutdown control input (SHDN) is low. The TC125/TC126 are available in a small 5-Pin SOT-23 package, occupy minimum board space and use small external components. The TC125 accepts input voltages from 2V to 10V. The TC126 accepts input voltages from 2.2V to 10V. Both the TC125 and TC126 have a start-up voltage of 0.9V at light load.