The MAX1946 single current-limited switch with auto-reset
supplies a guaranteed 500mA load in accordance
with USB specifications. The MAX1946 operates from a
2.7V to 5.5V input supply and consumes only 40µA of
quiescent current when operating and only 3µA in shutdown.
Selectable active-high/active-low control logic
and shutdown control provide additional flexibility. An
autoreset feature latches the switch off in the event of a
short circuit, saving system power. The switch reactivates
upon removal of the shorted condition.
The MAX1946 provides several safety features to protect
the USB port. Built-in thermal-overload protection
turns off the switch when the die temperature exceeds
+160°C. Accurate internal current-limiting circuitry protects
the input supply against both overload and short-circuit
conditions. An open-drain fault signal, (active-low FAULT),
notifies the microprocessor (µP) when a thermal overload,
current-limit, undervoltage lockout (UVLO), or
short-circuit fault occurs. A 20ms fault-blanking feature
enables the circuit to ignore momentary faults, such as
those caused when hot-swapping a capacitive load,
preventing false alarms to the host system. The fault-blanking
feature prevents fault signals from being
issued when the device powers up the load.
The MAX1946 is available in a space-saving 8-pin
TDFN package and operates over the extended (-40°C
to +85°C) temperature range.
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