The ISL6557A provides core-voltage regulation by driving up to four interleaved synchronous-rectified buck-converter channels in parallel. Intersil multi-phase controllers together with Intersil MOSFET drivers form the basis for the most reliable power-suppply solutions available to power the latest industry-leading microprocessors. Multi-phase buck converter architecture uses interleaved timing to multiply ripple frequency and reduce input and output ripple currents. Lower ripple results in lower total component cost, reduced dissipation, and smaller implementation area. Preconfigured for 4-phase operation, the ISL6557A offers the flexibility of selectable 2- or 3-phase operation. Simply connect the unused PWM pins to VCC. The channel switching frequency is adjustable in the range of 50kHz to igMHz giving the designer the ultimate flexibility in managing the balance between high-speed response and good thermal management.

New features on the ISL6557A include Dynamic-VID™ technology allowing seamless on-the-fly VID changes with no need for any additional external components. When the ISL6557A receives a new VID code, it incrementally steps the output voltage to the new level. Dynamic VID changes are fast and reliable with no output voltage overshoot or undershoot. The RGND and VSEN pins provide inputs for differential remote voltage sensing to improve regulation and protection accuracy. A threshold-sensitive enable pin (EN) can be used with an external resistor divider to optionally set the power-on voltage level. This allows optional start-up coordination with Intersil MOSFET drivers or any other devices powered from a separate supply.

Like other Intersil multiphase controllers, the ISL6557A uses cost and space-saving rDS(ON) sensing for channel current balance, dynamic voltage positioning, and overcurrent protection. Channel current balancing is automatic and accurate with the integrated current-balance control system. Overcurrent protection can be tailored to any application with no need for additional parts. The IOUT pin carries a signal proportional to load current and can be optionally connected to FB for accurate load-line regulation.

An integrated DAC decodes the 5-bit logic signal present at VID4-VID0 and provides an accurate reference for precision voltage regulation. The high-bandwidth error amplifier, differential remote-sensing amplifier, and accurate voltage reference all work together to provide better than 0.8% total system accuracy, and to enable the fastest transient response available.

• Multi-Phase Power Conversion
• Active Channel Current Balancing
• Precision rDS(ON) Current Sensing
  • Low Cost
  • Lossless
• Precision CORE Voltage Regulation
  • Differential Remote Voltage Sensing
  • ±0.8% System Accuracy
• Microprocessor Voltage Identification Input
  • Dynamic VID technology
  • 5-Bit VID Input
  • 0.800V to 1.550V in 25mV Steps
• Programmable Power-On Bias Level
• Programmable Droop Voltage
• Fast Transient Recovery Time
• Precision Enable Threshold
• Overcurrent Protection
• 2-, 3-, or 4-Phase Operation
• High Ripple Frequency. Channel Frequency Times Number Channels (100kHz to 6MHz)
• Pb-free available