The LTC4380 ultralow quiescent current (IQ) surge stopper provides compact overvoltage and overcurrent protection for always-on 4V to 72V electronics in automotive, industrial and avionic systems. The device replaces traditional shunt circuits composed of inductors, capacitors, transient voltage suppressors (TVS), and fuses with a single IC and series N-channel MOSFET. Current consumption is 8 µA in normal operation and 6 µA in shutdown mode. The low current allows a large filtering resistor to the device supply pin, enabling operation through automotive cold crank and overvoltage transients above 100V.
During an output overload or short-circuit, the LTC4380 regulates the forward path to a current limit set by a sense resistor. For sustained overvoltage or overcurrent conditions, a MOSFET stress-accelerated timeout ensures safe turn-off of the MOSFET. In contrast, traditional protection circuits may blow a fuse or burn out the TVS, requiring repairs.
The LTC4380 withstands a reversed input, such as an incorrectly inserted battery, to -60V. Adjustable input undervoltage lockout threshold blocks start-up for out-of-range voltages, avoiding deeply discharged batteries. The device also controls inrush current during hot plug of a circuit board’s power supply.
The LTC4380 is available in four options: the LTC4380-1 and LTC4380-2 have a pin-selectable clamp voltage, while the LTC4380-3 and LTC4380-4 clamp voltage is set with an input Zener diode. After a fault, the LTC4380-1 and LTC4380-3 latch the MOSFET off, while the LTC4380-2 and LTC4380-4 automatically turn on with a 0.1% duty cycle. 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 LTC4380 is offered in 10-pin MSOP and 3 mm x 3 mm DFN packages. Pricing starts at $2.48 each/1,000. For more information, visit http://www.linear.com/product/LTC4380
Linear Technology Corp.