MAX1703

19-1336; Rev 2; 11/98 NUAL KIT MA ATION EET H S A EVALU T WS DA FOLLO 1-Cell to 3-Cell, High-Power (1.5A), Low-Noise, Step-Up DC-DC Converter ____________________________Features o Up to 95% Efficiency o Up to 1.5A Output o Fixed 5V or Adjustable Step-Up Output (2.5V to 5.5V) o 0.7V to 5.5V Input Range o Low-Power Mode (300µW) o Low-Noise, Constant-Frequency Mode (300kHz) o Synchronizable Switching Frequency (200kHz to 400kHz) o 1µA Logic-Controlled Shutdown o Power-Good Comparator o Uncommitted Gain Block ________________General Description The MAX1703 is a high-efficiency, low-noise, step-up DC-DC converter intended for use in battery-powered wireless applications. It uses a synchronous-rectified pulse-width-modulation (PWM) boost topology to generate a 2.5V to 5.5V output from battery inputs, such as one to three NiCd/NiMH cells or one Li-Ion cell. The device includes a 2A, 75m Ω , N-channel MOSFET switch and a 140mΩ, P-channel synchronous rectifier. With its internal synchronous rectifier, the MAX1703 delivers up to 5% better efficiency than similar nonsynchronous converters. It also features a pulse-frequencymodulation (PFM) low-power mode to improve efficiency at light loads, and a 1µA shutdown mode. The MAX1703 comes in a 16-pin narrow SO package and includes an uncommitted comparator that generates a power-good or low-battery-warning output. It also contains a linear gain block that can be used to build a linear regulator. For lower-power outputs and a smaller pack...