RT2518
Operation
The RT2518 is a low input voltage low dropout LDO that
can support the input voltage range from 1.4V to 6V and
the output current can be up to 1.2A. The RT2518 uses
internal charge pump to achieve low input voltage operation
and the internal compensation network is well designed
to achieve fast transient response with good stability.
In steady-state operation, the feedback voltage is
regulated to the reference voltage by the internal regulator.
When the feedback voltage signal is less than the
reference, the on resistance of the power MOSFET is
decreased to increase the output current through the power
MOSFET, and the feedback voltage will be charge back to
reference. If the feedback voltage is less than the
reference, the power MOSFET current is decreased to
make the output voltage discharge back to reference by
the loading current.
Reverse Current Protection
The reverse current protection is guarantee by the N-
MOSFET with bulk capacitors connected to GND and the
internal circuit. The reverse voltage detection circuit shuts
the total loop down if the output voltage is higher than
input voltage.
Output Under-Voltage Protection (UVP) and Over-
Current Fold-Back
When the feedback voltage is lower than 0.15V after
internal soft-start end, the UVP is triggered. If the over-
current condition is trigged during UVP state, the OC limit
current will be decreased to limit the output power and
change into re-soft start state at the same time.
Soft-Start
At start-up, an internal current source charges an internal
capacitor to build the soft-start ramp voltage.
The output tracks the internal soft-start ramp voltage, which
limits the input inrush current.
The output ramp-up time proportional to the targeted
regulation voltage. With an output voltage range of 0.5V
to 5V, the typical ramp-up time will be around 50μs to
400μs, correspondingly.
Over-Temperature Protection (OTP)
The RT2518 has an over-temperature protection. When
the device triggers the OTP, the device shuts down until
the temperature back to normal and move to re-soft start
state.
Copyright
©
2016 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS2518-05 August 2017
www.richtek.com
3
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
