General Description

The APW6021 provides the power control and protection for four output voltages in high-performance, graphics intensive microprocessor and computer applications. The IC integrates voltage-mode PWM controller and three linear controllers, as well as the monitoring and protection functions into a 28-pin SOIC package. The PWM controller regulates the microprocessor core voltage with a synchronous-rectified buck converter. The linear controllers regulate the computer system’s AGP 1.5V or 3.3V bus power, the 1.5V GTL bus power, and the 1.8V power for the North/South Bridge core voltage and/or cache memory circuits.

Functional

? 4 Regulated Voltages are provided

? Microprocessor Core (1.3V to 3.5V)

? AGP Bus (1.5V or 3.3V)

? Memory (1.8V)

? GTL Bus (1.5V)

? Linear Controllers Drives with both MOSFET and Bipolar Series Pass Transistors

? Fixed or Externally Resistor-Adjustable Linear Outputs (FIX Pin)

? 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

? Core PWM Output: ± 1 Over Temperature

? Other Outputs: ± 3 Over Temperature

? TTL-Compatible 5- Bit DAC Microprocessor Core Output Voltage Selection

? Wide Range - 1.3VDC to 3.5 VDC

? Power-Good Output Voltage Monitor

? Over-Voltage and Over-Current Fault Monitors

? Switching Regulator Does Not Require Extra Current Sensing Element, Uses MOSFET’s rDS(ON)

? Small Converter Size

? Constant Frequency Operation

? 200kHz Free-Running Oscillator; Program mable From 50kHz to Over 1MHz