MP20049 – ULTRA-LOW NOISE, HIGH PSRR 150mA LINEAR REGULATOR IN 0.8x0.8mm WLCSP
MP20049 Rev. 1.11 www.MonolithicPower.com 10
9/10/2014 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2014 MPS. All Rights Reserved.
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 be
calculated using the following equation:
P
(MAX)
= (T
Junction
- T
Ambient
) /
JA
Where (T
Junction
- T
Ambient
) is the temperature
difference between the junction and the
surrounding environment,
JA
is the thermal
resistance from the junction to the ambient
environment. Connecting the GND pin of
MP20049 to ground with a large ground plane
will help the channel heat away.
Input Capacitor Selection
Using a capacitor whose value is >1µF on the
MP20049 input and the amount of capacitance
can be increased without limit. 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 MP20049 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. For
the application circuit, the MP20049 requires a
minimum capacitance of 0.7F with an ESR of
1 or less.
Output Noise and PSRR
For MP20049, an internal 50pF bypass
capacitor with new innovative structure reduces
output noises greatly, without the need for an
external bypass capacitor. The power supply
rejection is 75dB at 10kHz and 55dB at 100kHz.
