The MAX1715 PWM controller provides the high efficiency, excellent transient response, and high DC output accuracy needed for stepping down high-voltage batteries to generate low-voltage CPU core, I/O, and chipset RAM supplies in notebook computers. Maxim's proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns "instant-on" response to load transients while maintaining a relatively constant switching frequency. The MAX1715 achieves high efficiency at a reduced cost by eliminating the current-sense resistor found in traditional current-mode PWMs. Efficiency is further enhanced by its ability to drive very large synchronous-rectifier MOSFETs. Single-stage buck conversion allows this device to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size. The MAX1715 is intended for CPU core, chipset, DRAM, or other low-voltage supplies as low as 1V. The MAX1715 is available in a 28-pin QSOP package. For applications requiring VID compliance or DAC control of output voltage, refer to the MAX1710/MAX1711 data sheet. For a single-output version, refer to the MAX1714 data sheet. Applications * 1.8V and 2.5V I/O Supplies * Chipset/RAM Supplies as Low as 1V * CPU Core Supplies * Notebook Computers * Ultra-High Efficiency * No Current-Sense Resistor (lossless ILIMIT) * Quick-PWM with 100ns Load-Step Response * 1% VOUT Accuracy over Line and Load * Dual-Mode Fixed 1.8V/3.3V/Adj or 2.5V/Adj Outputs * Adjustable 1V to 5.5V Output Range * 2V to 28V Battery Input Range * 200/300/420/540kHz Nominal Switching Frequency * Over/Undervoltage Protection * 1.7ms Digital Soft-Start * Drives Large Synchronous-Rectifier FETs * Power-Good Indicator