ISL6308A Datasheet, PDF (1/28 Pages) Intersil Corporation – Three-Phase Buck PWM Controller with High Current Integrated MOSFET Drivers

ISL6308A
®
Data Sheet
September 9, 2008
FN6669.0
Three-Phase Buck PWM Controller with
High Current Integrated MOSFET Drivers
The ISL6308A is a three-phase PWM control IC with
integrated MOSFET drivers. It provides a precision voltage
regulation system for multiple applications including, but not
limited to, high current low voltage point-of-load converters,
embedded applications and other general purpose low
voltage medium to high current applications.The integration
of power MOSFET drivers into the controller IC marks a
departure from the separate PWM controller and driver
configuration of previous multi-phase product families. By
reducing the number of external parts, this integration allows
for a cost and space saving power management solution.
Output voltage can be programmed using the on-chip DAC
or an external precision reference. A two bit code programs
the DAC reference to one of 4 possible values (0.6V,
0.9V,1.2V and 1.5V). A unity gain, differential amplifier is
provided for remote voltage sensing, compensating for any
potential difference between remote and local grounds. The
output voltage can also be offset through the use of single
external resistor. An optional droop function is also
implemented and can be disabled for applications having
less stringent output voltage variation requirements or
experiencing less severe step loads.
A unique feature of the ISL6308A is the combined use of
both DCR and r_DS(ON) current sensing. Load line voltage
positioning and overcurrent protection are accomplished
through continuous inductor DCR current sensing, while
r_DS(ON) current sensing is used for accurate channel-current
balance. Using both methods of current sampling utilizes the
best advantages of each technique.
Protection features of this controller IC include a set of
sophisticated overvoltage and overcurrent protection.
Overvoltage results in the converter turning the lower
MOSFETs ON to clamp the rising output voltage and protect
the load. An OVP output is also provided to drive an optional
crowbar device. The overcurrent protection level is set
through a single external resistor. Other protection features
include protection against an open circuit on the remote
sensing inputs. Combined, these features provide advanced
protection for the output load.
Features
• Integrated Multi-Phase Power Conversion
- 1-, 2-, or 3-Phase Operation
• Precision Output Voltage Regulation
- Differential Remote Voltage Sensing
- ±0.8% System Accuracy Over-Temperature
(for REF=0.6V and 0.9V)
- ±0.5% System Accuracy Over-Temperature
(for REF=1.2V and 1.5V)
- Usable for Output Voltages not Exceeding 2.3V
- Adjustable Reference-Voltage Offset
• Precision Channel Current Sharing
- Uses Loss-Less r_DS(ON) Current Sampling
• Optional Load Line (Droop) Programming
- Uses Loss-Less Inductor DCR Current Sampling
• Variable Gate-Drive Bias - 5V to 12V
• Internal or External Reference Voltage Setting
- On-Chip Adjustable Fixed DAC Reference Voltage with
2-bit Logic Input Selects from Four Fixed Reference
Voltages (0.6V, 0.9V, 1.2V, 1.5V)
- Reference can be Changed Dynamically
- Can use an External Voltage Reference
• Overcurrent Protection
• Multi-tiered Overvoltage Protection
- OVP Pin to Drive Optional Crowbar Device
• Selectable Operation Frequency up to 1.5MHz per Phase
• Digital Soft-Start
• Capable of Start-up in a Pre-Biased Load
• Pb-Free (RoHS Compliant)
Applications
• High Current DDR/Chipset Core Voltage Regulators
• High Current, Low Voltage DC/DC Converters
• High Current, Low Voltage FPGA/ASIC DC/DC Converters
Ordering Information
PART
NUMBER
PART
MARKING
TEMP. RANGE
(°C)
PACKAGE
PKG.
DWG. #
ISL6308ACRZ* (Note)
ISL6308AIRZ* (Note)
6308A CRZ
6308A IRZ
0 to +70
-40 to +85
40 Ld 6x6 QFN (Pb-free)
40 Ld 6x6 QFN (Pb-free)
L40.6x6
L40.6x6
ISL6308AEVAL1Z
Evaluation Platform
*Add “-T” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
NOTE: These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil Pb-free
products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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