The ISL6521 provides the power control and protection for four output voltages in low-voltage, high-performance applications. The IC integrates a voltage-mode PWM controller and three linear controllers, as well as monitoring and protection functions into a 16-lead SOIC package. The PWM controller is intended to regulate the low voltage supply that requires the greatest amount of current (usually the core voltage for the FPGA, ASIC, or processor) with a synchronous rectified buck converter. The linears are intended to regulate other system voltages, such as I/O (input/output) and memory circuits. Both the switching regulator and linear voltage reference provide ±2% of static regulation over line, load, and temperature ranges. All outputs are user-adjustable by means of an external resistor divider. All linear controllers can supply up to 120mA with no external pass devices. Employing bipolar NPNs for the pass transistors, the linear regulators can achieve output currents of 3A or higher with proper device selection. The ISL6521 monitors all the output voltages. The PWM controller's adjustable overcurrent function monitors the output current by using the voltage drop across the upper MOSFET's rDS(ON). The linear regulator outputs are monitored via the FB pins for undervoltage events.