SC198A Datasheet, PDF (1/15 Pages) Semtech Corporation – Dual DC-DC Buck Converter with High Current Capability

POWER MANAGEMENT
Features
„ Input voltage range — 2.7V to 5.5V
„ Dual buck converters with independent control
„ High efficiency — over 90% peak
„ Up to 800mA Load
„ Programmable output voltages per channel — 8
„ Fixed-frequency operation — 1MHz
„ Optional SYNC clock input
„ Optional power-save under light-load conditions
„ Shutdown current <1μA
„ Soft-start to limit in-rush current
„ 4mm x 4mm MLPQ package
Applications
„ Mobile phones
„ Cordless phones
„ MP3 players
„ Digital cameras
„ PDAs
„ Single Li-Ion cell or (3) NiMH/NiCd cell devices
„ Digital multimedia broadcast (DMB) devices
„ Portable gaming systems
Typical Application Circuit
SC198A
Dual DC-DC Buck Converter
with High Current Capability
Description
The SC198A is a dual high-efficiency synchronous buck
converter designed for use in low power applications.
Each converter is capable of supplying up to 800mA of
average current at one of eight programmable output
voltages used as microprocessor supply voltages.
The SC198A uses a single control logic block for the two
converters, but their controls can be set independently.
The device uses a flexible clocking method allowing the
user to set the fixed internal 1MHz oscillator or synchro-
nize the clock to an external source. The device also has an
optional power-save mode that optimizes efficiency for
light loads.
The SC198A provides output voltage flexibility while con-
serving board space by using control pins to select the
output voltage. This eliminates at least four parts from the
traditional dual buck converter bill of materials.
VBATT
VINA ^SC198A
4.7μH
LXA
VINR
VOUTA
VINB
GNDA
C_IN
ENA
CTLA0
VOUTA
C_OUTA
CTLA1
CTLA2
4.7μH
LXB
VOUTB
ENB
CTLB0
VOUTB
GNDB
C_OUTB
CTLB1
CTLB2
GNDR
MODE/SYNC
September 26, 2007
1