ISL6537

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
- LDO Regulator for CPU/GMCH VTT Termination
• ACPI compliant sleep state control
• Glitch-free Transitions During State Changes
• Integrated VREF Buffer
• 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 Over-voltage Monitoring on All Outputs
• OCP on the Switching Regulator
• Integrated Thermal Shutdown Protection
• Pb-Free Available (RoHS Compliant)
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 1 • DSP supplies




Pinout






Specifications

5VSBY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .GND - 0.3V to +7V
P12V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .GND - 0.3V to +14V
Absolute Boot Voltage, VBOOT . . . . . . . . . . . . . . . . . . . . . . .+15.0V
Upper Driver Supply Voltage, VBOOT - VPHASE . . . . . . . . . . . +6.0V
All other Pins . . . . . . . . . . . . . . . . . . . .GND - 0.3V to 5VCC + 0.3V
ESD Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TBD




Description

The ISL6537 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. A buffered version of the VDDQ/2 reference is provided as VREF. Two LDO controllers ISL6537  are also integrated for the GMCH core voltage regulation and for the GMCH and CPU VTT termination voltage regulation. The switching PWM controller ISL6537  drives two N-Channel MOSFETs in a synchronous-rectified buck converter topology. The synchronous buck converter ISL6537  uses voltage-mode control with fast transient response. The switching regulator ISL6537 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 and 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.