The HIP6521 provides the power control and protection for four output voltages in high-performance microprocessor and computer applications. The IC integrates a voltage-mode PWM controller and three linear controllers, as well as monitoring and protection functions into a 16 Ld SOIC package. The PWM controller is intended to regulate the microprocessor memory core voltage with a synchronous-rectified buck converter. The linear controllers are intended to regulate the computer system’s AGP 1.5V bus power, the 2.5V clock power, and the 1.8V power for the North/South Bridge core voltage and/or cache memory circuits. Both the switching regulator and linear voltage references 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 employ bipolar NPNs for the pass transistors.

FEATUREs
• Provides 4 Regulated Voltages
    - Memory Core, AGP, Clock, and Memory Controller Hub Power
• ACPI Compatible
• Drives Bipolar Linear Pass Transistors
• Externally Resistor-Adjustable Outputs
• Simple Single-Loop Control Design
    - Voltage-Mode PWM Control
• Fast PWM Converter Transient Response
    - High-Bandwidth Error Amplifier
    - Full 0% to 100% Duty Ratio
• Excellent Output Voltage Regulation
    - All Outputs: 2% Over Temperature
• Overcurrent Fault Monitors
    - Switching Regulator Does Not Require Extra Current Sensing Element, Uses MOSFET’s rDS(ON)
• Small Converter Size
    - 300kHz Constant Frequency Operation
    - Small External Component Count
• Pb-Free Plus Anneal Available (RoHS Compliant)

APPLICATIONs
• Motherboard Power Regulation for Computers