MAX1700

19-4759; Rev 1; 1/99 L MANUA ION KIT HEET T A U L EVA TA S WS DA FOLLO 1-Cell to 3-Cell, High-Power (1A), Low-Noise, Step-Up DC-DC Converters General Description Features o Up to 96% Efficiency o 1.1 VIN Guaranteed Start-Up o 0.7V to 5.5V Input Range o Up to 800mA Output o Step-Up Output (adjustable from 2.5V to 5.5V) o PWM/PFM Synchronous-Rectified Topology o External Clock or Internal 300kHz Oscillator o 3µA Logic-Controlled Shutdown o Power-Good Output (MAX1701) o Low-Battery Comparator (MAX1701) o Uncommitted Gain Block (MAX1701) MAX1700/MAX1701 The MAX1700/MAX1701 are high-efficiency, low-noise, step-up DC-DC converters intended for use in batterypowered wireless applications. They use a synchronous-rectified pulse-width-modulation (PWM) boost topology to generate 2.5V to 5.5V outputs from battery inputs such as one to three NiCd/NiMH cells or one LiIon cell. Both devices have an internal 1A, 130mΩ Nchannel MOSFET switch and a 250m Ω P-channel synchronous rectifier. With their internal synchronous rectifier, the MAX1700/ MAX1701 deliver 5% better efficiency than similar nonsynchronous converters. They also feature a pulsefrequency-modulation (PFM) standby mode to improve efficiency at light loads, and a 3µA shutdown mode. The MAX1700/MAX1701 come in 16-pin QSOP packages (which occupy the same space as an 8-pin SO). The MAX1701 includes two comparators to generate power-good and low-battery warning outputs. It also contains a gain block that can be used to build a lin...