Description
The SC1403 is a multiple-output power supply controller designed to power battery operated systems. The SC1403 provides synchronous rectified buck converter control for two (3.3 V and 5 V) power supplies. An efficiency of 95% can be achieved for the two supplies. The SC1403 uses Semtech’s proprietary Virtual Current SenseTM 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. The SC1403 also provides a linear regulator for system housekeeping. The 5 V linear regulator takes its input from the battery; for 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 for maximum efficiency over wide load current range
◆ 5V / 50mA linear regulator
◆ Virtual Current Sense TM for enhanced stability
◆ Accurate low loss current limiting
◆ Out of phase switching reduces input capacitance requirements
◆ External compensation supports wide range of output filter components
◆ Programmable power-up sequence
◆ Power good output
◆ Output overvoltage & overcurrent protection with output undervoltage shutdown
◆ 4µA typical shutdown current
◆ 6mW typical quiescent power

APPLICATIONs
◆ Notebook and subnotebook computers
◆ Automotive electronics
◆ Desktop DC-DC converters