The LTC4368 replaces fuses, transient voltage suppressors and discrete circuitry, enabling a compact and comprehensive solution for shielding electronics from damaging overcurrent and over-, under- and reverse-voltage conditions. The LTC4368 controls back-to-back N-channel MOSFETs to provide a low loss current path during normal operation, turning them off for overcurrent faults in the forward or reverse direction. The LTC4368-1 circuit breaker provides symmetric forward and reverse current thresholds to protect batteries from excessive charge and discharge currents. The LTC4368-2 circuit breaker trips off when reverse current is detected to prevent backfeeding and hold up the output.
The LTC4368 quickly disconnects the load from input voltages exceeding an adjustable and precise overvoltage threshold. Adjustable undervoltage lockout disables operation for low input voltages, avoiding deeply discharged batteries. Reverse supply protection isolates the load from batteries inserted with incorrect polarity, eliminating a diode in the power path. The eliminated diode drop and the 2.5V operation provide sufficient margin for riding through automotive cold crank conditions. Device current consumption is 80 µA in normal operation and 5 µA in shutdown mode, prolonging battery run and standby time. The LTC4368 also controls inrush current while hot-plugging a circuit board’s power supply.
The LTC4368 is available in two options: the LTC4368-1 provides a 50 mV reverse circuit breaker sense threshold, whereas the LTC4368-2 has a 3 mV reverse threshold. After an overcurrent fault, a pin configuration determines if the MOSFETs are latched off or turned on after a delay. Specified over the 0°C to 70°C commercial, −40°C to 85°C industrial, and −40°C to 125°C automotive temperature ranges, the LTC4368 is offered in 10-pin MSOP and 3 x 3 mm DFN packages for $1.99 (1000).
Linear Technology; www.linear.com/product/LTC4368