The NU3121 is a synchronous high-efficiency boost converter. It integrates two low on resistance power FETs: A 10-mΩ switching FET and a 16-mΩ rectifier FET. The NU3121 features a wide input voltage range from 2.9 V to 18 V to support applications powered with single-cell, two-cell Lithium ion/polymer batteries or 5V,9V,12V, 15V power supplies. The NU3121 has 10-A continuous switch current capability and provides output voltage up to 23V. It provides a small-size solution for portable equipment. The NU3121 uses fixed frequency peak current mode control with slope compensation integrated. At the light load, the device has two operation modes selected by the MODE pin. One is the pulse frequency modulation (PFM) mode to improve the efficiency and another one is forced PWM mode to avoid application problems caused by low switching frequency. The switching frequency is adjustable from 200kHz to 1 MHz. The NU3121 also implements a adjustable soft start function. In addition, the device provides 24.5-V output overvoltage protection, cycle-by-cycle overcurrent protection, and thermal shutdown protection.