MP6401 – 300mA LDO LINEAR REGULATOR WITH INTEGRATED RESET IC
APPLICATION INFORMATION
Adjustable Regulator Output
Output Capacitor Selection
The OUT voltage of MP6401 has two modes
available (fixed and adjustable output voltage).
When ADJ pin is connected to GND, the regulator
works in fixed voltage mode. The regulator output
voltage will equal to preset voltage (1.8V, 2.5V or
3.3V options). In fixed voltage mode, the
impedance between ADJ and ground should
always be less than 50kΩ. Generally, ADJ is
connected directly to ground.
The MP6401 is designed specifically to work with
very low ESR ceramic output capacitor 3.3uF
(min). For performance consideration, a large
ceramic capacitor such as 10uF is better. X7R or
X5R capacitor dielectric is recommended.
OUT Voltage Transient Immunity
The MP6401 can be immune to OUT pin short
negative transient. Typically, the immune duration
is 60us with 10mV overdriving. A shorter negative
When the ADJ pin is connected to the tap of an
external resistor divider, the regulator works in
adjustable voltage mode as shown in Fig 3. The
output voltage is selected by resistor divider, thus
transient can not make the
output assert.
RESET
R1 + R2
VOUT = 1.229×
R2
In adjustable voltage mode, R2 equal to 13kΩ is
recommended as a good tradeoff among stability,
accuracy and high-frequency PSRR. R2 should
be not greater than 100kΩ.
Power Dissipation
The power dissipation for any package depends
on the thermal resistance of the case and circuit
board, the temperature difference between the
junction and ambient air, and the rate of airflow.
The power dissipation across the device can be
represented by the equation:
P = (VIN - VOUT) ×IOUT
The allowable power dissipation can be
calculated using the following equation:
PD (MAX) = (TJ (MAX)-TA)/θJA
Where (TJ(MAX)-TA) is the temperature difference
between the junction and the ambient
environment, θJA is the thermal resistance from
the junction to the ambient environment.
Connecting the GND pin of MP6401 to ground
using a large pad or ground plane helps to
channel heat away.
MP6401 Rev. 1.0
9/7/2012
www.MonolithicPower.com
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© 2012 MPS. All Rights Reserved.
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