ISL9502A
®
Data Sheet
February 12, 2008
FN6642.0
Two-Phase PWM Controller for Graphics
Processor Units (GPU)
Features
• Precision Two-phase Buck PWM controller
- 0.5% System Accuracy Over-Temperature
- Active Voltage Positioning Capability
Increase in GPU clock frequency is accompanied by
associated increase in the demand for power and transient-
current slew rate. At the same time, the voltage tolerance
requirement during steady-state and transient operation is
becoming more stringent concerning advanced GPU. The
ISL9502A is a two-phase PWM controller with embedded
gate drivers, which is tailored to meet the power and
dynamic requirements. The two-phase buck converter uses
two interleaved channels to effectively double the output
voltage ripple frequency and thereby reduce output voltage
ripple amplitude with fewer components, lower component
cost, reduced power dissipation, and smaller real estate
area.
• Internal Gate Driver with 2A Driving Capability
• Superior Load Transient Response
• Dynamic Phase Adding/Dropping
• Voltage Selection Input
- 7-bit VSEL Input
- 0.500V to 1.500V in 25mV Steps
- Supports VSEL Change On-the-Fly
• Multiple Current-Sensing Schemes Supported
- Lossless Inductor DCR Current Sensing
- Precision Resistive Current Sensing
The heart of the ISL9502A is the patented R3 (Robust
Ripple Regulator®) modulator. Compared with the traditional
multi-phase buck regulator, R3 technology has the fastest
transient response. This is due to the R3 modulator
commanding variable switching frequency during a load
transient.
• Thermal Monitor
• User Programmable Switching Frequency
• Differential Remote GPU Voltage Sensing
• Static and Dynamic Current Sharing
• Overvoltage, Undervoltage and Overcurrent Protection
• Pb-Free (RoHS Compliant)
At heavy load operation of the active mode, ISL9502A
commands the two phase continuous conduction mode (CCM)
operation. While the pin SET3 is asserted at the medium or
light load, the ISL9502A smoothly disables one phase and
operates in a one-phase operation. Once in one-phase
operation, when the GPU further lowers the load current, the
ISL9502A enables diode emulation to maximize efficiency at
light load depending on the logic of SET1 and SET2.
Ordering Information
PART
NUMBER
(Note)
TEMP.
RANGE
(°C)
PART
MARKING
PACKAGE
(Pb-free)
PKG.
DWG. #
A 7-bit digital-to-analog converter (DAC) allows dynamic
adjustment of the output voltage from 0.500V to 1.500V with
25mV step. A 0.5% system accuracy of the core output
voltage over-temperature is achieved by the ISL9502A.
ISL9502AHRZ
ISL9502 AHRZ -10 to +100 48 Ld 7x7 QFN L48.7x7
ISL9502AHRZ-T* ISL9502 AHRZ -10 to +100 48 Ld 7x7 QFN L48.7x7
*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.
A unity-gain differential amplifier is provided for remote GPU
die sensing. This allows the voltage on the GPU die to be
accurately measured and regulated. Current sensing can be
realized using either lossless inductor DCR sensing or
precision resistor sensing. A single NTC thermistor network
can thermally compensate the gain and the time constant of
the DCR variations. Droop control, also referred to as
adaptive voltage positioning (AVP), is implemented in
ISL9502A to reduce output decoupling capacitors and
achieve more cost-effective transient-load regulation.
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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