DATASHEET ISL6353 FN6897 Rev 0.00 Multiphase PWM Regulator for VR12 DDR Memory Systems September 15, 2011 The ISL6353 is a three-phase PWM buck regulator controller for Features VR12 DDR memory applications. The multi-phase VR12 Serial Communications Bus implementation results in better system performance, superior thermal management, lower component cost and smaller PCB Precision Voltage Regulation area. - 5mV Steps with VID Fast/Slow Slew Rates Supports Two Current Sensing Methods The ISL6353 has two integrated power MOSFET drivers for implementing a cost effective and space saving power - Lossless Inductor DCR Current Sensing management solution. - Precision Resistor Current Sensing Programmable 1, 2 or 3-Phase Operation The PWM modulator of the ISL6353 is based on Intersils Robust 3 Ripple Regulator (R ) technology. Compared with the Adaptive Body Diode Conduction Time Reduction 3 traditional multi-phase buck regulator, the R modulator Superior Noise Immunity and Transient Response commands variable PWM switching frequency during load 3 Pin Programmable Output Voltage and Power State Mode transients, achieving faster transient response. R also naturally goes into pulse frequency modulation operation in light load Output Current Monitor and Thermal Monitor conditions to achieve higher light load efficiency. Differential Remote Voltage Sensing The ISL6353 is designed to be completely compliant with VR12 High Efficiency Across Entire Load Range specifications. The ISL6353 has a serial VID (SVID) bus Programmable Switching Frequency communicating with the CPU. The output can be programmed for Resistor Programmable VBOOT, Power State Operation, 1-, 2- or 3-phase interleaved operation. The output voltage and SVID Address Setting, I MAX 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 temperature compensation or accurate resistor current Pb-Free (RoHS Compliant) sensing. It also has remote voltage sense, adjustable switching frequency, current monitor, OC/OV protection and power-good. Applications Temperature monitor and thermal alert is available too. DDR Memory 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 2. ISL6353EVAL1Z EFFICIENCY vs LOAD FIGURE 1. FAST TRANSIENT RESPONSE FN6897 Rev 0.00 Page 1 of 30 September 15, 2011 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 FN6897 Rev 0.00 Page 2 of 30 September 15, 2011 PH1 PH2 PH1 PH3 PH2 PH3 VDD GND PAD VIN PGOOD VR ON VR HOT VDDP OVP