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

SC121属于集成电路（IC） > DC-DC 开关控制器。Semtech Corporation制造生产的SC121DC-DC 开关控制器PMIC（电源管理集成电路）DC 到 DC 开关式控制器是用于高效率电路的稳压 IC，其配置为生成高于（突升或步升）或低于（突降或步降）输入电源的输出电源电压。其他拓扑结构可能包括：降压-升压、反激、正激、Cuk、SEPIC、全桥、半桥和推挽式。这些器件不同于需要最小电压并“烧尽”多余电压的线性稳压器。