XR71211 Datasheet, PDF (9/12 Pages) Exar Corporation – 1.5A Ultra Low Dropout Voltage Regulator

XR71211
Power Good Flag
The XR71211 features a Power Good Flag output signaling
an abnormal operating condition. A low voltage on the
Power Good Flag output indicates:
• Output voltage VOUT is approximately 9% below its
expected value
• A thermal fault has occurred
The Power Good Flag output, is an open collector capable
of sinking in excess of 1mA.
Thermal Protection and Shutdown
The XR71211 includes a thermal shutdown circuitry in
order to restrict the device’s operating temperature within a
safe operating range. When activated, typically at 160°C,
the XR71211 is forced into a low power reset state with a
typical hysteresis of 30°C.
Combined with the short circuit current protection, it
reduces and limits the heating effects of over-temperature
and/or over-current conditions on the LDO and surrounding
circuits.
Output Current Limit Protection
The XR71211 integrates output current limit protection in
order to protect the system main power supply, the regula-
tor itself and the load from excessive current flow. This cur-
rent limit effectively keeps the flow of current in the circuit at
a safe level.
In short circuit conditions, the device will take additional
steps to limit input and power by disabling and re-enabling
the pass device until the short condition is removed and
normal operation can resume. Depending on the imped-
ance of the short, this short circuit protection function may
initiate operation between 10% and 50% of the targeted
output voltage.
Reverse Bias Protection
In addition to the standard protection features in these
devices, they also incorporate a reverse bias protection.
Most LDOs have a parasitic body diode that provides a
path from VOUT to VIN if the input is shorted to ground.
The XR71211 has a blocking diode to ensure that no high
discharge currents can occur between the output and the
input when the input is shorted to ground.
© 2014 Exar Corporation
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exar.com/XR71211
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