The MAX14544/MAX14545 are overcurrent detection
switches that can provide power to external accessories
while preventing the host device from damage due
to faulty overload conditions. These analog switches
feature a 270mω (typ) on-resistance and operate from
a +2.3V to +5.5V input voltage range. The selectable
current limit of 200mA or 400mA makes them ideal for
load-switching applications.
The MAX14544 has an autoretry feature, whereas the
MAX14545 has a latchoff feature. When the switch is off,
OUT can withstand 28V maximum. When the switch is on
and a load is connected to the port, a blanking time of
10.5ms ensures that the transient voltage settles down.
After this blanking time, if the voltage across the switch is
greater than the FLAG assertion voltage, the switch turns
off and then a FLAG is issued to the microprocessor.
After the retry time, the device recloses for the duration
of the blanking time to check if the load current is lower
than the limit. The MAX14544 repeats this cycle if the
overload condition is present. During the cycle, FLAG
remains asserted. The MAX14544 remains on after the
overload condition is removed and FLAG deasserts. For
the MAX14545, after the blanking time, the switch turns
off and then a FLAG is issued to the microprocessor. The
switch can be turned on again by cycling the power or the EN input.