ISL6353_14 Datasheet, PDF (1/30 Pages) Intersil Corporation – Multiphase PWM Regulator for VR12 DDR Memory Systems

Multiphase PWM Regulator for VR12 DDR Memory
Systems
ISL6353
The ISL6353 is a three-phase PWM buck regulator controller for
VR12 DDR memory applications. The multi-phase implementation
results in better system performance, superior thermal
management, lower component cost and smaller PCB area.
The ISL6353 has two integrated power MOSFET drivers for
implementing a cost effective and space saving power
management solution.
The PWM modulator of the ISL6353 is based on Intersil’s Robust
Ripple Regulator™ (R³) technology. Compared with the traditional
multi-phase buck regulator, the R³ modulator commands variable
PWM switching frequency during load transients, achieving faster
transient response. R³ also naturally goes into pulse frequency
modulation operation in light load conditions to achieve higher light
load efficiency.
The ISL6353 is designed to be completely compliant with VR12
specifications. The ISL6353 has a serial VID (SVID) bus
communicating with the CPU. The output can be programmed for
1-, 2- or 3-phase interleaved operation. The output voltage and
power state can also be controlled independent of the serial VID
bus.
The ISL6353 has several other key features. It supports DCR
current sensing with a single NTC thermistor for DCR
temperature compensation or accurate resistor current sensing.
It also has remote voltage sense, adjustable switching frequency,
current monitor, OC/OV protection and power-good. Temperature
monitor and thermal alert is available too.
Features
• VR12 Serial Communications Bus
• Precision Voltage Regulation
- 5mV Steps with VID Fast/Slow Slew Rates
• Supports Two Current Sensing Methods
- Lossless Inductor DCR Current Sensing
- Precision Resistor Current Sensing
• Programmable 1, 2 or 3-Phase Operation
• Adaptive Body Diode Conduction Time Reduction
• Superior Noise Immunity and Transient Response
• Pin Programmable Output Voltage and Power State Mode
• Output Current Monitor and Thermal Monitor
• Differential Remote Voltage Sensing
• High Efficiency Across Entire Load Range
• Programmable Switching Frequency
• Resistor Programmable VBOOT, Power State Operation, SVID
Address Setting, I_MAX
• Excellent Dynamic Current Balance Between Phases
• OCP/WOC, OVP, OT Alert, PGOOD
• Small Footprint 40 Ld 5x5 TQFN Package
• Pb-Free (RoHS Compliant)
Applications
• DDR Memory
COMP
200mV/DIV
VDDQ = 1.5V
50mV/DIV
PHASE1/2/3
5V/DIV
26A STEP LOAD
1V/DIV
20µs/DIV
FIGURE 1. FAST TRANSIENT RESPONSE
95
94 ^{1.5V PS1 2ph CCM}
1.5V PS0
93
92
1.5V PS2 1ph DE
91
1.35VPS0
90
89
1.35V PS1 2ph CCM
88
1.35VPS2 1ph DE
87
86
85
0
10 20 30 40 50 60 70 80
LOAD (A)
FIGURE 2. ISL6353EVAL1Z EFFICIENCY vs LOAD
FN6897.0
1
September 15, 2011
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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