Linear Technology Corp. introduces the LTC4362, a 2.5 to 5.5V
overvoltage and overcurrent protector designed to safeguard low voltage,
portable electronics from damaging input voltage transients and current surges.
Overvoltage events can occur due to power adapter failure or faults, or when
hot-plugging an ac adapter into a device's power input. Inadvertently plugging
the wrong power adapter into a device can potentially cause damage from
overvoltage or negative supply voltage. The LTC4362 utilizes a 2 percent
accurate 5.8V overvoltage threshold to detect an overvoltage event and responds
quickly within 1µs (max) to isolate the downstream components from the input.
Overvoltage protection of up to 28V is achieved with an internal, avalanche
rated, low RDS(ON) MOSFET, and rides through inductive cable
transients without requiring transient voltage suppressors (TVS) or other
external components in most applications. In addition, the LTC4362 monitors the
voltage drop across an internal current sense resistor to provide a 20 percent
accurate, 1.5A overcurrent threshold.
controls an internal 40mOhm N-channel MOSFET so that under normal operation it
provides a low loss path from the input to the load. Inrush current limiting is
achieved with a controlled gate voltage slew rate. If the voltage at the input
exceeds the overvoltage threshold of 5.8V, the GATE is pulled low within 1us to
protect the load. The LTC4362 features a soft shutdown controlled by the /ON
pin and provides a gate drive output for an optional external P-channel MOSFET
for reverse voltage protection. A power good output pin indicates gate turn on.
The LTC4362 is available in two options; the LTC4362-1 latches off after an
overcurrent event, whereas the LTC4362-2 performs an auto-retry following a
130ms delay. Following an overvoltage condition, both options automatically
restart with a start-up delay.
Specified over the full commercial and industrial
temperature ranges, the LTC4362 is offered in 8-pin, 2mm x 3mm DFN packages.
Evaluation boards and samples are available online. The LTC4362 is priced at
$1.60 each in 1,000-piece quantities, and is available today in production.