SC122 Datasheet, PDF (1/13 Pages) Semtech Corporation – Low Voltage Synchronous Boost Converter

POWER MANAGEMENT
Features
„ Input voltage — 0.7V to 1.6V
„ Minimum start-up voltage — 0.85V
„ Output voltage fixed at 3.3V
„ Peak input current limit — 350mA typically
„ Output current 95mA at V = 1.6V, 50mA at V = 0.9V
IN
IN
„ Efficiency up to 80%
„ Internal synchronous rectifier
„ Switching frequency — 1.2MHz
„ Power save (voltage hysteretic) control
„ Anti-ringing circuit
„ Operating supply current (measured at OUT) — 40μA
„ No forward conduction path during shutdown
„ MLPD-UT-6 1.5 × 2.0 × 0.6 (mm) package
„ Lead-free and halogen-free
„ WEEE and RoHS compliant
Applications
„ Electric toothbrushes
„ Personal medical products
„ Single-cell alkaline, NiCd, or NiMH applications
SC122
Low Voltage Synchronous
Boost Converter
Description
The SC122 is a high efficiency, low noise, synchronous
step-up DC-DC converter. It produces a fixed 3.3V output
from a single cell alkaline or NiMH battery. It features an
internal 1.2A switch and synchronous rectifier to achieve
high efficiency and to eliminate the need for an external
Schottky diode.
The SC122 operates exclusively in voltage-hysteretic
power save mode (PSAVE) for high efficiency under light
load conditions. It features anti-ringing circuitry for
reduced EMI in noise sensitive applications. While dis-
abled, the output remains in a high impedance state to
preserve the charge on the output capacitor. This permits
ultra-low idle quiescent currents in applications in which
the SC122 can be periodically enabled by an external con-
troller to recharge the output capacitor.
Low quiescent current is obtained despite a high 1.2MHz
operating frequency. Small external components and the
space saving MLPD-UT-6, 1.5×2.0×0.6 (mm) package,
make this device an excellent choice for small handheld
applications that require the longest possible battery life.
Typical Application Circuit
L1
Single
Cell
(1.2V)
C_IN
IN
EN
GND
LX
OUT
GND
SC122
February 1, 2010
© 2010 Semtech Corporation
3.3V
C_OUT
1