XRP6274 Datasheet, PDF (8/11 Pages) Exar Corporation – 2A Ultra Low Dropout Voltage Regulator

XRP6274
2A Ultra Low Dropout Voltage Regulator
input voltage falls below a lower boundary of
operation.
SOFT START
The XRP6274 features a soft-start which
controls the output voltage ramp and allows the
regulator to gradually reach the initial steady
state operating point. This reduces current
spikes and surges at start up due to output
capacitor inrush current. Internal sequencing
completes in 50us, and then the reference
voltage is linearly ramped over a period of
approximately 2ms.
The inrush current will be the lesser of the
current limit value or the current defined by the
equation below:
𝐼_{𝐼𝑁𝑅𝑈𝑆𝐻}
=
𝐶_{𝑂𝑈𝑇}
𝑉_{𝑂𝑈𝑇}
2000𝑢𝑠
POWER GOOD FLAG
The XRP6274 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.
OUTPUT CURRENT LIMIT PROTECTION
The XRP6274 integrates output current limit
protection in order to protect the system main
power supply, the regulator itself and the load
from excessive current flow. This current 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
impedance of the short, this short circuit
protection function may initiate operation
between 10% and 50% of the targeted output
voltage
THERMAL PROTECTION AND SHUTDOWN
The XRP6274 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
XRP6274 is forced into a low power reset state
with a typical hysteresis of 30 degrees.
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.
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
XRP6274 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.
© 2015 Exar Corporation
8/11
Rev. 2.0.0