Description
The SC1403 is a multiple-output power supply controller designed to power battery operated systems. The SC1403 provides synchronous buck converter control for two (3.3V and 5V) power supplies. An efficiency of 95% can be achieved for the two supplies. The SC1403 uses Semtech’s proprietary Virtual Current Sense™ technology along with external error amplifier compensation to achieve enhanced stability and DC accuracy over a wide range of output filter components while maintaining fixed frequency operation. Lossless current sensing can be used to eliminate current sense resistors and reduce cost. The SC1403 also provides a 5V linear regulator for system housekeeping. The 5V linear regulator is derived from the battery; for improved efficiency, the output is switched to the 5V output when available.

Features
◆ 3.3V and 5V dual synchronous outputs, resistor programmable to 2.5V
◆ Fixed frequency or PSAVE operation for maximum efficiency over wide load range
◆ 5V / 50mA linear regulator
◆ Virtual Current Sense™ for enhanced stability
◆ Lossless current limiting
◆ Out of phase switching reduces input capacitance
◆ External compensation supports wide range of output filter components
◆ Programmable power-up sequence
◆ Power Good output
◆ Output overvoltage and overcurrent protection with output undervoltage shutdown
◆ 6µA typical shutdown current
◆ 6mW typical quiescent power

Applications
◆ Notebook and subnotebook computers
◆ Tablet PCs
◆ Embedded applications