Current Limited Load Switch
Functional Block Diagram
AAT4612
IN
Over-
Temperature
Protection
OUT
Under-Voltage
Lockout
Current
Limit
ON
GND
Functional Description
The AAT4612 is a single channel current limited
load switch that protects against short circuits by
current limiting to a preset level. A patented fast
acting current limit loop limits the current in a frac-
tion of a microsecond and instantly resets to low
impedance once the short-circuit condition is
removed. The AAT4612 is internally protected from
thermal damage by an over-temperature detection
circuit. If the die temperature reaches the internal
thermal limit, the power device is switched off until
the die temperature cools to a level below the ther-
mal limit threshold. The device will thermal cycle
indefinitely until the over-current condition is
removed. The AAT4612 operates with input volt-
ages ranging from 2.4V to 5.5V which, along with
its extremely low operating current, makes it ideal
for battery-powered applications. In cases where
the input voltage drops below 2.4V, the AAT4612
MOSFET is protected from entering the saturated
region of operation by being automatically shut
down by an under-voltage lockout circuit.
The AAT4612 is ideally suited for protection of
peripheral ports such as USB, RS232, and parallel
ports.
4612.2006.09.1.3
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AAT [ ADVANCED ANALOG TECHNOLOGY, INC. ]
