SC453 Datasheet, PDF (1/23 Pages) Semtech Corporation – Portable, VID Programmed Single Phase Power Supply Controller

POWER MANAGEMENT
Description
The SC453 IC is a single chip high-performance Hysteretic
PWM controller. With its integrated SmartDriver™, it pow-
ers advanced graphics and core processors. It provides
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 pro-
vides the fastest possible transient response, while avoid-
ing the stability issues inherent to classical PWM control-
lers. The DAC is externally slew rate limited to minimize
transient currents and audible noise.
SC453
Portable, VID Programmed Single
Phase Power Supply Controller
Features
High Speed Hysteretic Controller
Single Phase Operation
Selectable Analog or VID Controlled Sleep Setting
6 Bit VID programmable Output
Integrated Drivers with Soft-High Side Turn-On
Programmable Soft-Start
Programmable Boot Voltage
Programmable Sleep Voltage with Sleep Mode
Under-Voltage Lockout on VCCA
Over-voltage Protection on CORE
Current Limit Protection on CORE
Thermal Protection
Power Good Flag with Blanking During
V_CORE Changes
Automatic Power Save at Light Load
TSSOP-28 Package
The SC453 operates from 5VDC and also features soft-
start, an open-drain PWRGD signal with power good blank-
ing, and an enable input. Programmable current limiting
shuts down the SC453 after 32 current limit pulses.
Applications
Low Power Notebook and Laptop Computers
Embedded Applications
PowerStep IV™ and Smart Driver™ are trademarks
of Semtech Corporation.
Typical Application Circuit
V₅
V_CCA
Smart
Driver
VIN
VCORE
0.700V-1.708V
SC453 Single Phase
Power Supply
PWM
Controller
VID (5:0)
VID Logic
and DAC
August 25, 2006
1
www.semtech.com