Features

• Replaces Power Schottky Diodes
• Controls N-Channel MOSFETs
• 0.3μs Turn-Off Time Limits Peak Fault Current
• Wide Operating Voltage Range: 9V to 80V
• Smooth Switchover without Oscillation
• No Reverse DC Current
• Monitors VIN, Fuse, and MOSFET Diode
• Available in 14-Lead (4mm × 3mm) DFN, 16-Lead MS and SO Packages

Typical Application

Description

The LTC4355 is a positive voltage ideal diode-OR controller that drives two external N-channel MOSFETs. Forming the diode-OR with N-channel MOSFETs instead of Schottky diodes reduces power consumption, heat dissipation and PC board area.

With the LTC4355, power sources can easily be ORed together to increase total system reliability. The LTC4355 can diode-OR two positive supplies or the return paths of two negative supplies, such as in a –48V system.

In the forward direction the LTC4355 controls the voltage drop across the MOSFET to ensure smooth current transfer from one path to the other without oscillation. If a power source fails or is shorted, fast turnoff minimizes reverse current transients.

Power fault detection indicates if the input supplies are not in regulation, the inline fuses are blown, or the voltages across the MOSFETs are greater than the fault threshold.