MP6402 –DUAL 500MA LDO LINEAR REGULATORS WITH INTEGRATED RESET IC
MP6402 Rev.1.0 www. MonolithicPower.com 12
4/8/2011 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
OPERATION
The MP6402 integrates two low-noise, low-
dropout, low-quiescent current linear regulators
with a reset circuit. It operates from a 2.5V to
5.5V input voltage. The dual-channel LDOs can
supply up to 500mA of load current. The internal
reset circuit is used to monitor the output voltage
of channel 2. The
becomes active (low)
when output voltage drops below its threshold.
The MP6402 uses the internal P-channel
MOSFET as the pass element and features
internal thermal shutdown and internal current
limit circuits.
Linear Regulator
The MP6402 integrates dual-channel LDOs. The
output voltages are fixed. Their values range
from 0.9V and 3.3V with ±1.5% accuracy. Each
channel of MP6402 can supply up to 500mA of
load current.
Reset Function
The reset circuit monitors the OUT2 pin voltage.
is a open-drain, active-low signal pin. It
should be connected to power supply through a
pull up resistor (R1 should be larger than 10kΩ).
becomes active (low) when output
voltage of channel 2 drops below its threshold.
The thermal shutdown will make the
active. When the activated triggering condition is
removed,
will become inactive after a
pre-set delay time. The delay time is
programmable through external capacitor
between ExtCap and GND.
EN Shutdown
The MP6402 can be switched ON or OFF by a
logic input at the EN pin. A high voltage at this
pin will turn the device on. When the EN pin is
low, the regulator is off and the supply current is
reduced. If this feature is not to be used, the EN
input should be tied to IN pin to keep the
regulator on at all time. Do not float the EN pin.
Current Limit
The MP6402 includes two independent current
limit structures which monitor and control the
gate voltage of the pass element to limit the
guaranteed maximum output current to 500mA.
Output Discharge
The part involves a discharge function that
provides a 100Ω resistive discharge path for the
external output capacitor. The function will be
active when the part is disabled and it will be
done in a very limited time.
Thermal Shutdown
Thermal protection turns off the pass element
when the junction temperature exceeds +150ºC,
allowing cooling the IC. When the IC’s junction
temperature drops by 20ºC, the pass element will
be turned on again. Thermal protection limits
total power dissipation in the MP6402. For
reliable operation, junction temperature should
be limited to 125 ºC maximum.
