LX8221 Microsemi Corporation, LX8221 Datasheet - Page 5

• Manufacturer Part Number: LX8221
• Description: Dual 150ma Cmos Low Dropout Regulator
• Manufacturer: Microsemi Corporation

Copyright © 2000
Rev. 1.1a, 2006-01-19
be calculated using the following equation:
is negligible)
For the MSOP package, thermal resistance, θ
when mounted on a FR4 copper clad PCB. Junction
temperature of the integrated circuit can be calculated
using:
Where:
Example: Given the following conditions:
(Note: power dissipation resulting from quiescent current
TM
T
V
V
I
P
OUT
D
A
IN
OUT
=
= 60°C
= 4.2V
= 100mA
(
= 2.7V
V
IN
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: [phone]
(
T
MAX
RISE
T
J
)
=
−
=
V
T
(
OUT
A
P
D
+
(
×
T
MIN
RISE
Θ
)
JA
)
×
)
I
OUT
(
MAX
)
JA
Integrated Products Division
is 206°C/W
A P P L I C A T I O N S
®
Microsemi
Dual 150mA CMOS Low Dropout Regulator
calculate the total power dissipation and junction
temperature:
Total Power Dissipation:
Junction Temperature:
Layout Consideration:
The layout must be implemented with low impedance paths
for V
traces to avoid voltage drops and pick up noise. Adding an
area of PCB copper to the GND pin (pin 8) will reduce the
overall θ
substrate. This will lower the device junction temperature
improving overall output voltage accuracy. The input/output
capacitors must be placed as close as possible to each
voltage regulator output pin.
IN
, V
JA
OUT
T
since it is thermally connected to the device
P
P
J
RODUCTION
D
=
and Ground by creating sufficiently wide
=
60
(
4
o
C
2 .
+
V
(
. 0
−
15
2
7 .
W
D
V
×
ATA
)
206
×
0
1 .
o
S
C
A
HEET
/
=
W
. 0
)
=
15
91
W
o
C
LX8221
Page 5