2-Cell Alkaline & USB-Compatible Low Loss Power Controller from Linear Technology

The LTC3101 features a wide input operating range of 1.8V to 5.5V, compatible with two or three AA or AAA form factor battery cells in Nickel, Lithium or alkaline chemistries, standard 1-cell Li-Ion/Polymer prismatic batteries, plus USB or 5V wall adapter input power. Additionally, the device’s low loss PowerPath control seamlessly and automatically manages power flow between these multiple input sources. The always-alive VMAX and LDO outputs provide power for critical functions or additional external regulators. Internal sequencing and independent enable pins provide flexible power-up options.

The LTC3101’s buck-boost regulator can deliver up to 800mA continuously for input voltages above 3V and is ideal for efficiently regulating a 3.0V or 3.3V output over the full 1.8V to 5.5V input voltage range. The LTC3101’s two buck regulators feature 100% duty cycle operation and are capable of delivering output currents of 350mA each, with adjustable output voltages down to 0.6V. The LTC3101’s internal low RDS(ON) switches enable buck-boost efficiencies up to 95% and buck regulator efficiencies up to 93%, maximizing battery run time. In addition, Burst Mode® operation optimizes efficiency at light loads with a total IC quiescent current of only 38uA with all regulators enabled and only 15uA in standby with the LDO and VMAX outputs active. The high 1.27MHz switching frequency allows the use of tiny low cost capacitors and inductors less than 1mm in height. Furthermore, all regulators are stable with ceramic output capacitors, achieving very low output voltage ripple.