Switches simplify complex power designs

The FPF1038/FPF1039 advanced load management switches reduce in-rush current, or high di/dt, when a switch is used to disconnect loads with high (>100-µF) output capacitances. If the load is connected directly to a battery or power supply using a conventional MOSFET/discrete solution, the tolerances of discrete components can create conditions where excessive droop can cause voltage rails to go out of regulation as the switch turns on and draws large currents. The FPF1038/9 prevents this from occurring by integrating the necessary functionality into one chip, requiring less board space, reducing part counts, and eliminating tolerance matching issues.

The parts integrate a slew-rate controlled low-impedance MOSFET switch (21 mΩ typical). The optimized slew-rate controlled turn-on characteristics with TR=2.7 ms prevent voltage droop on supply rails with bulk capacitances as large as 200 µF. Other features include a power consumption of less than 1 µA, a load discharge path, ESD protection, GPIO/CMOS compatible-enable circuitry, and an input range from 1.2 to 5.5 V. ($0.60 ea/1,000 — samples available now.)

Fairchild Semiconductor , South Portland , ME
Sales 207-775-8100
http://www.fairchildsemi.com