The EL7571 is a flexible, high efficiency, current mode, PWM step down controller. It incorporates five bit DAC adjustable output voltage control which conforms to the Intel Voltage Regulation Module (VRM) Specification for Pentium II and Pentium Pro class processors. The controller employs synchronous rectification to deliver efficiencies greater than 90% over a wide range of supply voltages and load conditions. The on-board oscillator frequency is externally adjustable, or may be slaved to a system clock, allowing optimization of RFI performance in critical applications. In single supply operation, the high side FET driver supports boot-strapped operation. For maximum flexibility, system operation is possible from either a 5V rail, a single 12V rail, or dual supply rails with the controller operating from 12V and the power FETs from 5V.