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