MIC49150-1.2BR Micrel Inc, MIC49150-1.2BR Datasheet - Page 10

• Manufacturer Part Number: MIC49150-1.2BR
• Description: IC REG LDO 1.5A 1.2V SPAK-5
• Manufacturer: Micrel Inc

Specifications of MIC49150-1.2BR

• Regulator Topology: Positive Fixed
• Voltage - Output: 1.2V
• Voltage - Input: Up to 6.5V
• Voltage - Dropout (typical): 0.28V @ 1.5A
• Number Of Regulators: 1
• Current - Output: 1.5A
• Current - Limit (min): 1.6A
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SPAK-5
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

capacitor of at least 1µF is needed directly between the
input and regulator ground. Refer to “ Application Note 9 ”
for further details and examples on thermal design and
heat sink specification.
Minimum Load Current
The
regulators, does not require a minimum load to maintain
output voltage regulation.
Power MSOP-8 Thermal Characteristics
One of the secrets of the MIC49150’s performance is its
power MSOP-8 package featuring half the thermal
resistance of a standard MSOP-8 package. Lower
thermal resistance means more output current or higher
input voltage for a given package size.
Lower thermal resistance is achieved by joining the four
ground leads with the die attach paddle to create a
single-piece electrical and thermal conductor. This
concept has been used by MOSFET manufacturers for
years, proving very reliable and cost effective for the
user.
Thermal resistance consists of two main elements, θ
(junction-to-case thermal resistance) and θ
ambient thermal resistance). See Figure 1. θ
resistance from the die to the leads of the package. θ
is the resistance from the leads to the ambient air and it
includes θ
(sink-to-ambient thermal resistance).
Using the power MSOP-8 reduces the θ
and allows the user to reduce θ
resistance, θ
is the limiting factor in calculating the maximum power
dissipation capability of the device. Typically, the power
MSOP-8 has a θ
than the standard MSOP-8 which is typically 160°C/W.
θ
soldered directly to a ground plane which significantly
reduces the case-to-sink thermal resistance and sink to
ambient thermal resistance.
Low-dropout linear regulators from Micrel are rated to a
maximum junction temperature of 125°C. It is important
not to exceed this maximum junction temperature during
operation of the device. To prevent this maximum
junction
appropriate ground plane heat sink must be used.
Micrel, Inc.
CA
November 2006
is reduced because pins 5 through 8 can now be
MIC49150,
temperature
CS
JA
(case-to-sink thermal resistance) and θ
(junction-to-ambient thermal resistance)
JA
unlike
of 80°C/W, this is significantly lower
from
most
being
CA
other
. The total thermal
exceeded,
JC
high
CA
dramatically
(case-to-
JC
current
is the
the
CA
SA
JC
10
Figure 2 shows copper area versus power dissipation
with each trace corresponding to a different temperature
rise above ambient.
From these curves, the minimum area of copper
necessary for the part to operate safely can be
determined. The maximum allowable temperature rise
must be calculated to determine operation along which
curve.
Figure 2. Copper Area vs. Power-MSOP
Figure 3. Copper Area vs. Power-MSOP
Figure 1. Thermal Resistance
printed circuit board
MSOP-8
900
800
700
600
500
400
300
200
100
900
800
700
600
500
400
300
200
100
Power Dissipation (∆T
0
0
Power Dissipation (T
0
0
T J = 125°C
0.25 0.50 0.75 1.00 1.25 1.50
q
0.25 0.50 0.75 1.00 1.25 1.50
POWER DISSIPATION (W)
POWER DISSIPATION (W)
JC
85°C
q
JA
q
CA
50°C 25°C
AMBIENT
A
JA
)
)
M9999-111306
heat sink area
ground plane
MIC49150