Linear Technology introduces the LTC4364 surge stopper

Date
07/24/2012

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N-channel MOSFET replaces Schottky diode

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The LTC4364 surge stopper shields downstream electronics from input over voltages and over current, enabling continuous operation through transient surges.

The LTC4364, a surge stopper that behaves nearly like an ideal diode, provides compact, low-loss protection for 4V to 80V electronics in automotive, avionics, and industrial systems. The surge stopper shields downstream electronics from input over voltages and over current, enabling continuous operation through transient surges. Over-current limiting protects the system and supply from ?short-circuits at the load. Unique to the LTC4364 is a near-ideal diode emulation, which replaces a Schottky diode in the power path with a low-loss N-channel MOSFET. The ideal diode, along with a robust front-end, protects the load from a reversed input to -40 V and maintains the output voltage during an input brownout. During an input voltage surge, such as automotive load dump, the LTC4364 drops the excess voltage across an external MOSFET while regulating the output to an adjustable safe voltage. This enables the use of lower voltage rated electronics downstream. Similarly, during a current surge, the LTC4364 regulates the forward path to a current limit set by a sense resistor. For persistent over-voltage or over-current conditions, a VDS-accelerated timer with early warning indicator ensures safe shutdown of the MOSFET. The LTC4364's wide operating range maintains operation in automotive cold crank when the battery voltage could dip down to 4V. With a simple input clamp, the device can handle transient surges beyond 100V and can even survive -20V at the output. Adjustable input under-voltage and over-voltage thresholds block ?start-up for out-of-range voltages, avoiding deeply discharged batteries and auto-retry into a fault condition. A low 370 μA operating and 10 μA shutdown current prolongs battery life. The device can also provide inrush current control for HotSwap applications. The LTC4364 is available in two options. After a fault, the LTC4364-1 latches off the pass transistor, whereas the LTC4364-2 enables a 0.1% duty cycle auto-retry. Linear Technology specifies the LTC4364 over the full commercial, industrial and automotive temperature ranges and offers the IC in 14-pin 4 x 3 mm DFN, MSOP-16, and SO-16 packages. Pricing begins at $3.45 (1000) and the device is available in production quantities. Evaluation boards are available online or from your local sales office. Linear Technology Corporation

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