PWM Controller. SC2647 Datasheet
The SC2647 provides microprocessor core voltage
regulation solution up to 4 paralleled PWM channels. The
solution can also be configured as 2, 3, or 4-phase form.
Multi-phase buck regulator utilizes the phase-shift tim-
ing control to allow interleaved switching of the power
switches. This architecture minimizes the core voltage
ripple and the input current ripple, which leads to opti-
mized voltage regulator design for power density, tran-
sient responses, and the thermal performances.
To satisfy the highly dynamic nature of the modern
microprocessors, the SC2647 adopts peak current mode
control topology which ensures wide control loop
bandwidth and fast transient responses. The current
mode control provides intrinsic phase current matching.
The maximum ripple frequency is greater than 1MHz.
One of the outstanding features of the SC2647 is its
voltage regulation accuracy. Not only it provides better
than 0.5% set point accuracy, but also the accuracy to
fully complaint with the stringent load line slope
specifications mandated by the modern microprocessors.
Lossless output current sensing ensures the regulator
output voltage is accurately positioned according to the
load current condition, and an internal temperature
compensation technology further enhances the perfor-
mance of voltage accuracy.
The patented Combi-SenseTM topology is employed by
SC2647. The MOSFET Rds(on) and the output inductor
winding resistance is used to generate the phase cur-
rent information. The SC1211VX Combi-SenseTM MOSFET
driver plus the SC2647 enables the complete solution.
The SC2647 is a multi-platform controller. It conforms
to Intel VRM/VRD10.0, VRM9.X, and AMD K-8 (OpteronTM)
VID specifications. With very minor changes of the sche-
matic and the layout, the SC2647 based solution can be
ported form one platform to another. This greatly ben-
efits the system manufactures for reductions of design
cycle and minimize the inventory management.
Multi-Phase PWM Controller
The VID structure of the SC2647 supports VID-on-Fly ap-
plications for any platform. The cycle-by-cycle current
limit plus the intelligent over current shut down provide
the maximum versatility of the system without false
tripping under all possible changes of VID and load
conditions. The differential voltage feedback sense
eliminates the error caused by high load current on the
ground plane. External offset is easy to achieve for any
platforms and the VID settings. The enable function is
also provided to interface with the corresponding sys-
tem signal for correct start up timing and shut down
(Multiple Patents Pending)
VRD/VRM10.0, VRM9.X, and K-8 compliant
Core Voltage Set Point Accuracy 0.5%
Combi-SenseTM Current Mode Control
Intrinsic Phase Current Matching
Fast Transient Responses
Active Droop with Temperature Compensation to
Meet Load Line Slope
Support VID-on-Fly with 5 or 6 bit VID
Enable Function for Power Sequencing
Cycle-by-Cycle Peak Current Limit
Intelligent Over Current Shut Down
Over Voltage Protection When Using Semtech
Under Voltage Protection Built in
External programmable Soft-Start
Externally programmable switching frequency.
2, 3, or 4-Phase Configurations
24-Pin SOIC or TSSOP Packages
This device is fully WEEE and RoHS Compliant
Voltage Regulator VRD/VRM10.0
Voltage Regulator VRM9.X
Voltage Regulator K-8
High Current, Low Voltage Step Down DC/DC
July, 12, 2006
Typical Application Circuit
© 2006 Semtech Corp.