Description
The SC121 is a high efficiency, low noise, synchronous step-up DC-DC converter that provides boosted voltage levels in low-voltage handheld applications. The wide input voltage range allows use in systems with single NiMH or alkaline battery cells as well as in systems with higher voltage battery supplies. It features an internal 1.2A switch and synchronous rectifi er to achieve up to 94% efficiency and to eliminate the need for an external Schottky diode. The output voltage can be set to 3.3V with internal feedback, or to any voltage within the specified range using a standard resistor divider.

FEATUREs
■ Input voltage — 0.7V to 4.5V
■ Minimum start-up voltage — 0.85V
■ Output voltage — fixed at 3.3V; adjustable from 1.8V to 5.0V
■ Peak input current limit — 1.2A
■ Output current at 3.3 VOUT — 80mA with VIN = 1.0V, 190mA with VIN = 1.5V
■ Forced PWM operation at all loads
■ Efficiency up to 94%
■ Internal synchronous rectifier
■ No forward conduction path during shutdown
■ Switching frequency — 1.2MHz
■ Soft-start startup current limiting
■ Shutdown current — 0.1μA (typ)
■ Ultra-thin 1.5 × 2.0 × 0.6 (mm) MLPD-UT-6 package
■ Lead-free and halogen-free
■ WEEE and RoHS compliant

Applications
■ MP3 players
■ Smart phones and cellular phones
■ Palmtop computers and handheld instruments
■ PCMCIA cards and memory cards
■ Digital cordless phones
■ Personal medical products
■ Wireless VoIP phones
■ Small motors