Latest Technologies

Linear Technology has introduced LT4356-3 -- an overvoltage protection regulator with overcurrent protection and inrush current limiting for high availability systems. The LT4356-3 is a new option offering latchoff operation under fault conditions, and is the latest member of a family of products designed to suppress high voltage surges and currents to protect downstream electronics from damage.

The LT4356-3 provides an energy-efficient barrier to limit the amount of electrical and thermal energy available to electrical equipment, an important requirement in Intrinsic Safety applications. The device provides an active barrier that, under normal operation, passes input power directly to the load with very little loss, said the company.

During an overvoltage event, the LT4356-3 regulates the output to a user-defined voltage by controlling the gate of an external N-Channel MOSFET. Inrush current limiting is achieved by controlling the voltage slew rate of the gate. The LT4356-3 monitors voltage drop across a current sense resistor at the input of the circuit to protect against overcurrent faults. For either an overvoltage or overcurrent fault condition, an integrated fault timer ensures safe shutdown of the MOSFET if the fault persists. For complete conformance to the Intrinsic Safety specification, the LT4356-3 is offered in a 16-pin SOIC package, addressing the high voltage pin spacing requirements. Using two devices in series meets the redundancy requirements of the specification.

The LT4356-3 offers a wide input operating range of 4V to 80V, and can handle transient voltages of 100V and higher, in addition to providing reverse input protection to -60V without damage to itself or the load. The LT4356-3 is ideal for automotive, industrial, avionics and intrinsic safety applications, as well as positive high voltage distributed power Hot Swap systems.

An auxiliary amplifier is provided for additional design flexibility. The LT4356-3 can be used as a voltage detection comparator or as a low dropout (LDO) linear regulator controller. The LT4356 is available in three options, defined by the function of the shutdown pin. For the LT4356-1 (auto-retry) and LT4356-3 (latchoff option), shutdown of the device reduces the quiescent current to 7uA. For the LT4356-2 with auto-retry, the auxiliary amplifier and internal reference remain active to ensure a keep-alive supply voltage for vital functions when the main system is shut down. Quiescent current is reduced to 60uA during shutdown.

Specified over the full commercial, industrial, automotive and military temperature ranges, all three versions of the LT4356 are offered in (4mm x 3mm) 12-pin DFN, 10-pin MSOP and 16-pin SOIC packages. Pricing begins at $1.98 each for 1,000-piece quantities and the device is available in production quantities.