ACPI Regulator/Controller for
Dual Channel DDR Memory Systems
The ISL6532 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
and integrated LDO to supply VDDQ with high current during
S0/S1 states and standby current during S3 state. During
Run mode, 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.
The switching PWM controller drives two N-Channel
MOSFETs in a synchronous-rectified buck converter
topology. The synchronous buck converter uses voltage-
mode control with fast transient response. Both the switching
regulator and integrated standby LDO provide 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.
Switching the memory core output between the PWM
regulator and the standby LDO during state transitions is
accomplished smoothly via the internal ACPI control
circuitry. The NCH signal provides synchronized switching of
a backfeed blocking switch during the transitions eliminating
the need to route 5V Dual to the memory supply.
An integrated soft-start feature brings VDDQ into regulation in
a controlled manner when returning to S0/S1 state from
S4/S5 or mechanical off states. During S0 the PGOOD signal
indicates that all supplies are within spec and operational.
Each output is monitored for under and over-voltage events.
Current limiting is included on the VTT and VDDQ standby
regulators. Thermal shutdown is integrated.
ISL6532 (QFN) TOP VIEW
20 19 18 17 16
6 7 8 9 10
• Generates 2 Regulated Voltages
- Synchronous Buck PWM Controller with Standby LDO
- 3A Integrated Sink/Source Linear Regulator with
Accurate VDDQ/2 Divider Reference.
- Glitch-free Transitions During State Changes
• ACPI Compliant Sleep State Control
• Integrated VREF Buffer
• PWM Controller Drives Low Cost N-Channel MOSFETs
• 250kHz Constant Frequency Operation
• Tight Output Voltage Regulation
- Both Outputs: ±2% Over Temperature
• 5V or 3.3V Down Conversion
• 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
• Over Current Protection and Under/Over-Voltage
Monitoring of Both Outputs
• Integrated Thermal Shutdown Protection
• QFN Package Option
- QFN Compliant to JEDEC PUB95 MO-220 QFN - Quad
Flat No Leads - Product Outline
- QFN Near Chip Scale Package Footprint; Improves
PCB Efficiency, Thinner in Profile
• 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
0 to 70 20 Ld 6x6 QFN
1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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