MP2009-ULTRA LOW NOISE, LOW DROPOUT,120mA LINEAR REGULATOR
APPLICATION INFORMATION
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 = (V
IN
- V
OUT
)
×I
OUT
The allowable power dissipation can
calculated using the following equation:
P
(MAX)
= (T
Junction
- T
Ambient
) /
θ
JA
be
bypass capacitor for space-limiting applications.
The power supply rejection is 75dB at 10kHz and
55dB at 100kHz. (See the PSRR vs. Frequency
graph
in
the
Typical
Performance
Characteristics).
Input Capacitor Selection
Use a 1µF capacitor on the input of the MP2009.
Larger values will help to improve line transient
response with the drawback of increased size.
Ceramic capacitors are preferred, but tantalum
capacitors may also suffice.
Output Capacitor Selection
The MP2009 is designed specifically to work with
very low ESR ceramic output capacitor in space-
limiting and performance consideration. Output
capacitor of larger values will help to improve
load transient response and reduce noise with
the drawback of increased size. A 1µF ceramic
capacitor with ESR lower than 3Ω is sufficient for
the MP2009 application circuit. (See the Region
of Stable C
OUT
ESR vs. Load Current graph in the
Typical Performance Characteristics)
Where (T
Junction
- T
Ambient
) is the temperature
difference between the junction and the
surrounding environment,
θ
JA
is the thermal
resistance from the junction to the ambient
environment. Connecting the GND pin of
MP2009 to ground with a large ground plane will
help the channel heat away.
Output Noise and PSRR
For the MP2009, an internal 50pF bypass
capacitor with new innovative structure reduces
output noises greatly. It does not need external
MP2009 Rev. 1.2
12/18/2013
www.MonolithicPower.com
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