VRM8.5 Dual PWM and Dual Linear Power System Controller

The ISL6523A provides the power control and protection for four output voltages in high-performance microprocessor and computer applications. The IC integrates two PWM controllers and two linear controllers, as well as the monitoring and protection functions into a 28-pin SOIC package. One PWM controller regulates the microprocessor core voltage with a synchronous-rectified buck converter. The second PWM controller supplies the computer system’s AGTL+ 1.2V bus power with a standard buck converter. The linear controllers regulate power for the 1.5V AGP bus and the 1.8V power for the chipset core voltage and/or cache memory circuits.

Features

• Provides 4 Regulated Voltages

- Microprocessor Core, AGTL+ Bus, AGP Bus Power,

and North/South Bridge Core

• Drives N-Channel MOSFETs

• Linear Regulator Drives Compatible with both MOSFET

and Bipolar Series Pass Transistors

• Simple Single-Loop Control Designs

- Voltage-Mode PWM Control

• Fast PWM Converter Transient Response

- High-Bandwidth Error Amplifiers

- Full 0 to 100 Duty Ratios

• Excellent Output Voltage Regulation

- Core PWM Output . . . . . . . . . . ±1 Over Temperature

- All Other Outputs . . . . . . . . . . . . . ±3 Over Temperature

• VRM8.5 TTL-Compatible 5-Bit DAC Microprocessor Core

Output Voltage Selection

- Wide Range . . . . . . . . . . . . . . . . . . . . 1.050V to 1.825V

• Power-Good Output Voltage Monitors

- Separate delayed VTT Power Good

• Overcurrent Fault Monitors

- Switching Regulators Do Not Require Extra Current

Sensing Elements, Use MOSFET’s rDS(ON)

• Small Converter Size

- Constant Frequency Operation

- 200kHz Internal Oscillator

Applications

• Motherboard Power Regulation for Computers