Linear Technology Corporation has introduced the LTC4371, a diode-OR controller for dual-feed high-power telecom and datacom boards. The LTC4371 provides seamless handoff between redundant power supplies, replacing power Schottky diodes and associated heat sinks with N-channel MOSFETs, significantly reducing power loss, voltage drop and solution size.
The controller is designed to withstand ±300V or higher voltage transients experienced during lightning-induced surges, load switching or supply short-circuit, for the most rugged diode-OR solution available. A built-in shunt-regulated supply with low 350µA quiescent current and high impedance drain pins enables large-value external resistors to safely limit device current during such high voltage transients. External transient voltage suppressors are eliminated, saving cost and board area.
The LTC4371 serves a low 15mV forward voltage drop across the ideal diode MOSFETs to minimize power dissipation in high-current applications. The linear servo technique blocks DC reverse current while ensuring smooth current transfer during supply switchover. During an input supply short-circuit, transient reverse current is minimized by a 2 A gate turn-off current. A strong 5mA gate pull-up current ensures rapid turn-on of the MOSFET, enabling AC rectification applications. Operating voltage range extends into the hundreds of volts due to the internal shunt regulator, while a 4.5 V minimum supply accommodates low voltage -5 V and -12 V ORing applications.
Specified over the 0°C to 70°C commercial and -40 °C to 85 °C industrial temperature ranges, the LTC4371 is offered in 10-pin MSOP and 3 mm x 3 mm DFN plastic packages. 1,000-piece pricing starts at $2.50 each. Device samples and evaluation circuit boards are available.