SC197 Datasheet, PDF (1/20 Pages) Semtech Corporation – 3.5MHz, 500mA Synchronous Dual Step-Down DC-DC Regulator

SC197
POWER MANAGEMENT
3.5MHz, 500mA Synchronous
Dual Step-Down DC-DC Regulator
Features
Description
 Input Voltage — 2.9V to 5.5V
 Output Voltage — 0.8V to 3.3V
 Output current capability — 500mA per regulator
 Efficiency up to 94%
 Programmable output voltages — 15
 High light-load efficiency via automatic PSAVE mode
 Fast transient response
 Oscillator frequency — 3.5MHz
 100% duty cycle capability
 Quiescent current — 38µA typical per regulator
 Shutdown current — 0.1µA typical per regulator
 Internal soft-start
 Over-voltage protection
 Current limit and short circuit protection
 Over-temperature protection
 Under-voltage lockout
 Floating control pin protection
 MLPQ-UT18 2.0 x 3.0 x 0.6 (mm) package
 Lead-free, halogen-free, and RoHS/WEEE compliant
Applications
 Smart phones and cellular phones
 MP3/Personal media players
 Personal navigation devices
 Digital cameras
 Single Li-ion cell or 3 NiMH/NiCd cell devices
 Devices with 3.3V or 5V internal power rails
The SC197 contains two identical high efficiency 500mA
step-down regulators designed for use in battery-
powered applications. Each regulator includes 15
programmable output voltage settings that can be
selected using the four control pins, eliminating the need
for external feedback resistors. The output voltage can be
fixed to a single setting or dynamically switched between
different levels. Pulling all four control pins low disables
the output.
The SC197 operates at a fixed 3.5MHz switching frequency
in normal PWM (Pulse-Width Modulation) mode. A vari-
able frequency PSAVE (Power Save) mode is used to
optimize efficiency at light loads for each output setting.
Built-in hysteresis prevents chattering between the two
modes.
The SC197 provides several protection features to safe-
guard the device under stressed conditions. These include
short circuit protection, over-temperature protection,
under-voltage lockout, and soft-start to control in-rush
current. These features, coupled with the small 2.0 x 3.0 x
0.6 (mm) package make the SC197 a versatile device ideal
for step-down regulation in products needing high effi-
ciency and a small PCB footprint.
Typical Application Circuit
V_IN
2.9V to 5.5V
Control Logic
For Output A
V_IN
2.9V to 5.5V
Control Logic
For Output B
C_INA
4.7µF
SC197
INA
LXA
OUTA
CTL3A
CTL2A
CTL1A
CTL0A
GNDA
INB
C_INB
4.7µF
CTL3B
CTL2B
CTL1B
CTL0B
LXB
OUTB
GNDB
L_XA
1.0µH
L_XB
1.0µH
V_OUTA
0.8V to 3.3V
C_OUTA
10µF
V_OUTB
0.8V to 3.3V
C_OUTB
10µF
January 17, 2011
© 2011 Semtech Corporation