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SC2646B Datasheet, PDF (1/9 Pages) Semtech Corporation – 2, 3 or 4 Phase Combi-Sense PWM Controller | |||
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POWER MANAGEMENT
Description
The SC2646B controller provides a microprocessor core
voltage regulation solution for up to 4 paralleled PWM
channels. The solution can be configured in 2, 3, or 4-
phase form. This multi-phase buck regulator utilizes
phase-shift timing control to allow interleaved switching
of the power switches. The productâs architecture mini-
mizes the core voltage ripple and the input current ripple,
which leads to optimized voltage regulator design for
power density, transient responses, and thermal
performances.
To satisfy the highly dynamic nature of the modern micro-
processors, the SC2646B adopts peak current mode
control topology which ensures wide control loop band-
width and fast transient responses. The current mode
control provides intrinsic phase current matching. The
maximum ripple frequency is greater than 2MHz.
SC2646B
2, 3 or 4 Phase
Combi-SenseTM PWM Controller
Features
 VRD/VRM10.X compliant
 Core Voltage Set Point Accuracy 0.5%
 Combi-SenseTM Current Mode Control
 Intrinsic Phase Current Matching
 Fast Transient Responses
 Active Droop to Meet Load Line Slope
 Enable Function for Power Sequencing
 Cycle-by-Cycle Peak Current Limit
 Intelligent Over Current Shut Down
 Over Voltage Protection When Using Semtech
Combi-SenseTM Driver SC1211
 Under Voltage Protection Built in
 Externally Programmable Soft-Start
 Externally Programmable Switching Frequency
 2, 3, or 4-Phase Configurations
 24-Pin TSSOP Package
One of the outstanding features of the SC2646B device
is its voltage regulation accuracy. Not only does it pro-
vide 0.5% set point accuracy, but also the accuracy to
be fully compliant with stringent load line slope specifi-
cations mandated by the modern microprocessors.
Lossless output current sensing ensures the regulator
output voltage is accurately positioned according to the
load current condition.
Semtechâs patented Combi-SenseTM topology is employed
by SC2646B controller. The MOSFET Rds(on) and the out-
put inductor winding resistance is used to generate the
phase current information. Semtechâs SC1211 Combi-
SenseTM MOSFET driver works with the SC2646B to en-
able a complete solution.
Combi-SenseTM is a Trademark of Semtech Corporation
Applications
 Voltage Regulator VRD/VRM10.X
 Voltage Regulation Modules
 High Current, Low Voltage Step Down DC/DC
Converters
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 the VID settings. The enable func-
tion is also provided to interface with the corresponding
system signal for correct start up timing and shut down
timing.
Revision: Apr. 11, 2005
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