Multiphase PWM Regulator for VR12 DDR Memory Systems ISL6353 Features The ISL6353 is a three-phase PWM buck regulator controller for VR12 Serial Communications Bus VR12 DDR memory applications. The multi-phase implementation Precision Voltage Regulation results in better system performance, superior thermal - 5mV Steps with VID Fast/Slow Slew Rates management, lower component cost and smaller PCB area. Supports Two Current Sensing Methods The ISL6353 has two integrated power MOSFET drivers for - Lossless Inductor DCR Current Sensing implementing a cost effective and space saving power - Precision Resistor Current Sensing management solution. Programmable 1, 2 or 3-Phase Operation The PWM modulator of the ISL6353 is based on Intersils Robust Adaptive Body Diode Conduction Time Reduction 3 Ripple Regulator (R ) technology. Compared with the traditional Superior Noise Immunity and Transient Response 3 multi-phase buck regulator, the R modulator commands variable Pin Programmable Output Voltage and Power State Mode PWM switching frequency during load transients, achieving faster 3 transient response. R also naturally goes into pulse frequency Output Current Monitor and Thermal Monitor modulation operation in light load conditions to achieve higher light Differential Remote Voltage Sensing load efficiency. High Efficiency Across Entire Load Range The ISL6353 is designed to be completely compliant with VR12 Programmable Switching Frequency specifications. The ISL6353 has a serial VID (SVID) bus Resistor Programmable VBOOT, Power State Operation, SVID communicating with the CPU. The output can be programmed for Address Setting, I MAX 1-, 2- or 3-phase interleaved operation. The output voltage and power state can also be controlled independent of the serial VID Excellent Dynamic Current Balance Between Phases bus. OCP/WOC, OVP, OT Alert, PGOOD The ISL6353 has several other key features. It supports DCR Small Footprint 40 Ld 5x5 TQFN Package current sensing with a single NTC thermistor for DCR Pb-Free (RoHS Compliant) temperature compensation or accurate resistor current sensing. It also has remote voltage sense, adjustable switching frequency, Applications current monitor, OC/OV protection and power-good. Temperature DDR Memory monitor and thermal alert is available too. 95 1.5V PS0 COMP 1.5V PS1 2ph CCM 94 200mV/DIV 93 92 1.5V PS2 1ph DE 91 VDDQ = 1.5V 1.35VPS0 50mV/DIV 90 89 PHASE1/2/3 1.35V PS1 2ph CCM 5V/DIV 88 1.35VPS2 1ph DE 87 86 26A STEP LOAD 85 1V/DIV 0 10 20304050607080 20s/DIV LOAD (A) FIGURE 1. FAST TRANSIENT RESPONSE FIGURE 2. ISL6353EVAL1Z EFFICIENCY vs LOAD FN6897.0 CAUTION: These devices are sensitive to electrostatic discharge follow proper IC Handling Procedures. 1 1-888-INTERSIL or 1-888-468-3774 Copyright Intersil Americas Inc. 2011. All Rights Reserved September 15, 2011 Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. EFFICIENCY (%)ISL6353 Simplified Application Circuit Using Inductor DCR Current Sensing +5V VIN +5V DUAL DUAL VIN (5VSB/12V DUAL) ADDR PROG2 BOOT1 PROG1 UG1 RNTC PH1 NTC C PH1 VO1 SDA LG1 ALERT P GND SCLK +12V VW COMP BOOT2 UG2 FB PH2 VDDQ PH2 VO2 ISL6353 LG2 VCCSENSE VSEN GND VSSSENSE RTN +5V +12V FB2 BOOT VCTRL UGATE VCC PHASE ISL6596 ISEN1 GND DRIVER ISEN2 PWM PWM3 LGATE ISEN3 PH3 VO3 VSET1 VSUMN VO1 VSET2 ISUMN VO2 PSI VO3 C ISUMP IMON September 15, 2011 2 FN6897.0 PH1 PH2 PH1 PH3 PH2 PH3 VDD GND PAD VIN PGOOD VR ON VR HOT VDDP OVP