AAT4682 Datasheet, PDF (7/10 Pages) Advanced Analogic Technologies – Dual Electronic Resettable Switches

Functional Block Diagram
AAT4682
Dual Electronic Resettable Switch
INA
ILIM
UVLO
OTMP
ILIM
3ms Blanking
3ms Blanking
OUTB
OUTB
FAULTA
FAULTB
GND
Functional Description
The AAT4682 is a dual channel electronic reset-
table fuse that protects against short-circuit condi-
tions by current limiting to a preset level. A patent-
ed fast acting current limit loop limits load current in
a fraction of a microsecond and instantly resets
back to a low impedance state once the short-cir-
cuit condition is removed. A current limit condition
is reported by the open drain FAULT output after a
two millisecond blanking interval. The blanking
prevents false reporting during the charging of a
capacitive load, which typically occurs when a load
is connected. The AAT4682 is internally protected
from thermal damage by an over-temperature
detection circuit. If the die temperature reaches the
internal thermal limit, both power devices are
switched off until the die temperature cools to a
level below the thermal limit threshold. The device
will thermal cycle indefinitely until the over-current
condition is removed. Due to the high thermal con-
ductivity of silicon and the size of the die, the tem-
perature across the die is relatively uniform at high
temperatures; therefore, as a precaution, both
power devices are switched off when the thermal
threshold is reached. The AAT4682 operates with
input voltages ranging from 1.8V 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 1.8V,
the AAT4682 internal MOSFETs are protected from
entering the saturated region of operation by being
automatically shut down by an under-voltage lock-
out circuit.
The AAT4682 is ideally suited for protection of
peripheral ports such as USB, RS232, and parallel
ports.
4682.2006.05.1.2
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