The MAX1992/MAX1993 pulse-width modulation (PWM) controllers provide high efficiency, excellent transient response, and extremely high DC output accuracy. The device steps off a high-voltage battery to generate a low-voltage CPU core or supplies a computer with a laptop chipset/RAM. Maxim's proprietary Quick-PWM™ fast-acting, constant-time PWM control scheme handles wide input/output voltage ratios with ease, providing 100ns "instant" load transient response, while maintaining a relatively constant switching frequency. Efficiency is enhanced by a very large drive capability of the synchronousrectifierMOSFET. Current sensing is used in the same series to ensure reliable overload and inductor saturation protection using an external current sensing resistor output. In addition, the controller can sense current throughout the synchronous rectification or use a lossless inductor to detect the lowest power dissipation. The single-stage step-down conversion allows the MAX1992/MAX1993 to step down directly for the highest possible efficiency for high-voltage batteries. In addition, switching in two stages (supplying the rail from another system, not the battery) maximum switching frequency allows the smallest possible physical size. The MAX1992 powers the CPU core, chipset, memory, or power rails as low as 0.7V. The MAX1993 powers the chipset and graphics processor core, which requires dynamically adjustable output voltage. The MAX1993 provides a tracking input that can actively terminate the use of the bus. The MAX1992/MAX1993 are available with optional overvoltage and undervoltage protection in the 24-pin thin QFN package. For dual step-down PWM controllers, inductor saturation protection, external reference input voltage, and dynamically selectable output voltages, see the MAX1540/MAX1541 data sheets.