Low Iq Surge Stopper for High Reliability Current Sensitive Applications

Protecting sensitive electronic circuitry from voltage transients is an essential part of any system, be it automotive, industrial, avionic or battery-powered portable applications. We offer a wide variety of solutions for these applications with the Surge Stopper family. LTC4380 is the exciting new member of this family, providing voltage suppression as well as current limit, being fully operational with only 8µA of quiescent current. While traditional protection circuitry relies on bulky inductors, capacitors, fuses and transient voltage suppressors (TVS) to clamp the transient, the LTC4380 protects by regulating a series N-channel MOSFET.

The LTC4380 is a high voltage surge stopper and current limiter with two pin-selectable gate clamp thresholds of 31.5V and 50V (-1 and -2 option). The output voltage is clamped with the help of an external MOSFET controlled by the LTC4380. The LTC4380 can withstand surges up to hundreds of volts with the only limitation being the safe operating area (SOA) of the MOSFET. Once the output reaches the clamp voltage, a timer is started. When the timer expires, the LTC4380 turns off the MOSFET. The timer adapts to the stress placed on the MOSFET: a large voltage drop across the MOSFET with a large current results in a fast time out, while a small voltage drop with low current results in a longer ride out time. During operation, the entire circuit consumes only 8µA, and the device may be shut down to limit the current consumption to 6µA, making it the ideal solution for power conscious applications.

The LTC4380 is ideal for harsh industrial, automotive and avionic applications; the low quiescent current makes it especially suited to battery-powered and always-on systems. Applications include protection from automotive load dump, motor-induced transients, coupled overvoltages, incorrect input supplies and power supply failures.