AAT3221IJS-1.8-T1 View Datasheet(PDF) - Advanced Analogic Technologies
Part Name
Description
MFG CO.
'AAT3221IJS-1.8-T1' PDF : 16 Pages View PDF
PowerLinearTM
PRODUCT DATASHEET
AAT3221/2
150mA NanoPower™ LDO Linear Regulator
The power dissipation for a 150mA load occurring for
8.2% of the duty cycle will be 20.9mW. Finally, the two
power dissipation levels can summed to determine the
total true power dissipation under the varied load:
PD(total) = PD(100mA) + PD(150mA)
PD(total) = 229.5mW + 30.75mW
PD(total) = 260.25mW
The maximum power dissipation for the AAT3221/2
operating at an ambient temperature of 85°C is 267mW.
The device in this example will have a total power dis-
sipation of 260.25mW. This is within the thermal limits
for safe operation of the device.
Printed Circuit Board Layout
Recommendations
In order to obtain the maximum performance from the
AAT3221/2 LDO regulator, very careful attention must
be considered in regard to the printed circuit board lay-
out. If grounding connections are not properly made,
power supply ripple rejection and LDO regulator tran-
sient response can be compromised.
The LDO regulator external capacitors CIN and COUT
should be connected as directly as possible to the ground
pin of the LDO regulator. For maximum performance
with the AAT3221/2, the ground pin connection should
then be made directly back to the ground or common of
the source power supply. If a direct ground return path
is not possible due to printed circuit board layout limita-
tions, the LDO ground pin should then be connected to
the common ground plane in the application layout.
3221.2007.11.1.12
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