ISL6548
ACPI Regulator/Controller for Dual Channel DDR Memory Systems
Key Features
- Generates 4 Regulated Voltages
- Synchronous Buck PWM Controller for DDR VDDQ
- 3A Integrated Sink/Source Linear Regulator with Accurate VDDQ/2 Divider Reference for DDR VTT
- LDO Regulator for GMCH Core
- Sink/Source LDO Regulator for CPU/GMCH VTT Termination
- ACPI Compliant Sleep State Control
- Glitch-free Transitions During State Changes
- PWM Controller Drives Low Cost N-Channel MOSFETs
- 250kHz Constant Frequency Operation
- Tight Output Voltage Regulation
- All Outputs: ±2% Over Temperature
- Fully-Adjustable Outputs with Wide Voltage Range: Down to 0.8V supports DDR and DDR2 Specifications
- Simple Single-Loop Voltage-Mode PWM Control Design
- Fast PWM Converter Transient Response
- Under and Overvoltage Monitoring on All Outputs
- OCP on the Switching Regulator
- Integrated Thermal Shutdown Protection
- Pb-Free Plus Anneal Available (RoHS Compliant)
Description
The ISL6548 provides a complete ACPI compliant power solution for up to 4 DIMM dual channel DDR/DDR2 Memory systems. Included are both a synchronous buck controller to supply VDDQ during S0/S1 and S3 states. During S0/S1 state, a fully integrated sink-source regulator generates an accurate (VDDQ/2) high current VTT voltage without the need for a negative supply. Two LDO controllers are also integrated for the GMCH core voltage regulation and for the GMCH/CPU VTT termination voltage regulation.
The switching PWM controller drives two N-Channel MOSFETs in a synchronous-rectified buck converter topology. The synchronous buck converter uses voltagemode control with fast transient response. The switching regulator provides a maximum static regulation tolerance of ±2% over line, load, and temperature ranges. The output is user-adjustable by means of external resistors down to 0.8V.
An integrated soft-start feature brings all outputs into regulation in a controlled manner when returning to S0/S1 state from any sleep state. During S0 the VIDPGD signal indicates that the GMCH/CPU VTT termination voltage is within spec and operational.
Each output is monitored for undervoltage events. The switching regulator also has overvoltage and overcurrent protection. Thermal shutdown is integrated.
Applications
- Single and Dual Channel DDR Memory Power Systems in ACPI compliant PCs
- Graphics Cards - GPU and Memory Supplies
- ASIC Power Supplies
- Embedded Processor and I/O Supplies
- DSP Supplies
