ISL6523A

ISL6523A TM Data Sheet February 2002 FN9063 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. The ISL6523A includes an Intel VRM8.5 compatible, TTL 5-input digital-to-analog converter (DAC) that adjusts the microprocessor core-targeted PWM output voltage from 1.050V to 1.825V in 25mV steps. The precision reference and voltage-mode control provide ±1% static regulation. The second PWM controller’s output provides a voltage level of 1.2V with ±3% accuracy. The linear regulators use external N-channel MOSFETs or bipolar NPN pass transistors to provide fixed output voltages of 1.5V ±3% (VOUT3) and 1.8V ±3% (VOUT4). The ISL6523A monitors all the output voltages. A delayedrising VTT (standard buck output) Power Good signal is issued before the core PWM starts to ramp up. Another system Power Good signal is issued when the core is within ±10% of...