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SC450
Portable IMVP-IV™ and IMVP4+™
Dual Phase Power Supply Controller
POWER MANAGEMENT
Revision: May 21, 2004
Description Features
Applications
Typical Application Circuit
IMVP-IV™ and IMVP4+™ compliant single chip
solution
On chip CLK_ENABLE# and IMVP4_PWRGD outputs
Backward compatible with SC1476
High speed hysteretic controller
6 bit VID programmable output
Integrated drivers with soft high side turn-on
Programmable softstart
Programmable boot voltage
Programmable DeeperSleep voltage
Dynamic phase current matching
Under-voltage lockout on VccA
Over-voltage protection on CORE
Current Limit protection on CORE
Thermal protection
Powergood flag with blanking during VID or
DeeperSleep mode changes
Automatic powersave at light load
Slew rate limited DAC
TSSOP-38 package
The SC450 PowerStep IV™ IC is a single chip high-per-
formance Hysteretic PWM controller. With its integrated
SmartDriver™, it powers advanced IMVP-IV™ and
IMVP4+™ processors. The SC450 features extended Intel
Mobile Voltage Positioning (IMVP™) to increase battery
life by reducing the voltage at the processor when it is
heavily loaded. It directly supports Intel’s SpeedStep®
processors for even longer battery life. The SC450 fully
supports the Intel® Geyserville-III core voltage specifi-
cation. It provides direct “deeper sleep” mode and boot
voltage support. Automatic “power-save” is present to
prevent negative current flow in the low-side FET during
light loading conditions, saving even more power. The high
side driver initially turns on with a weak drive to reduce
ringing, EMI, and capacitive turn-on of the low side.
A 6-bit DAC, accurate to 0.85%, sets the output voltage
reference, and implements the 0.700V to 1.708V range
required by the processor. The hysteretic converter uses
a comparator without an error amplifier, and therefore
provides the fastest possible transient response, while
avoiding the stability issues inherent to classical PWM
controllers. The DAC is externally slew rate limited to mini-
mize transient currents and audible noise.
The SC450 operates from 3.3V and 5V. It also features
soft-start, an open-drain PWRGD signal with power-good
blanking, and an enable input. Programmable current
limiting shuts down the SC450 after 32 current limit
pulses. In addition, it comes in a space-saving TSSOP-
38 package.
SC1474
D ual P hase
Extended IMVP
CONTROLLER
VID [4 :0 ]
Lo
+VCORE
+V _IN
+V_5
0.600V -1.75V
U p to 4 0 A
Extended
IMVP
Logic
PW M
Contro ller
Pow er
Control
Signals
Sm art
Drive r
VID
Multiplexer
Lo
Co
Sm art
Drive r
Rcs
Rcs
+V_3
+V_VID
VID
R egulator
Contro ller
SC1474
D ual P hase
Extended IMVP
CONTROLLER
VID [4 :0 ]
Lo
+VCORE
+V _IN
+V_5
0.600V -1.75V
U p to 4 0 A
Extended
IMVP
Logic
PW M
Contro ller
Pow er
Control
Signals
Sm art
Drive r
VID
Multiplexer
Lo
Co
Sm art
Drive r
Rcs
Rcs
+V_3
+V_VID
VID
R egulator
Contro ller
VID[5:0]VID[5:0]
VID[5:0]VID[5:0]
VID[5:0]
Notebook and Laptop computers
Embedded applications
PowerStep IV™ and SmartDriver™ are trademarks of
Semtech Corporation.
Other trademarks or registered trademarks may be claimed
as the property of others.
