MIC5318-2.5YMT TR Micrel Inc, MIC5318-2.5YMT TR Datasheet - Page 9

• Manufacturer Part Number: MIC5318-2.5YMT TR
• Description: 6Vin, Single 300mA ULDO In 1.6mm X 1.6mm Thin MLFr ( )
• Manufacturer: Micrel Inc

Specifications of MIC5318-2.5YMT TR

• Regulator Topology: Positive Fixed
• Voltage - Output: 2.5V
• Voltage - Input: Up to 6V
• Voltage - Dropout (typical): 0.11V @ 300mA
• Number Of Regulators: 1
• Current - Output: 300mA
• Current - Limit (min): 340mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 6-TMLF®, QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MIC5318-2.5YMTTR; MIC5318-2.5YMTTR

September 2010
Thermal Considerations
The MIC5318 is designed to provide 300mA of
continuous current. Maximum ambient operating
temperature can be calculated based on the output
current and the voltage drop across the part. Given
that the input voltage is 3.3V, the output voltage is
2.8V and the output current = 300mA.
The actual power dissipation of the regulator circuit
can be determined using the equation:
Because this device is CMOS and the ground current
is typically <100µA over the load range, the power
dissipation contributed by the ground current is < 1%
and can be ignored for this calculation:
To determine the maximum ambient operating
temperature of the package, use the junction-to-
ambient thermal resistance of the device and the
following basic equation:
T
the die θ
The table below shows junction-to-ambient thermal
resistance for the MIC5318 in the 6-pin 1.6mm x
1.6mm Thin MLF
J(max)
6-Pin 1.6x1.6 Thin MLF
= 125°C, the maximum junction temperature of
P
P
P
P
JA
Package
D
D
D
D(MAX)
thermal resistance = 100°C/W.
= (V
= (3.3V – 2.8V) × 300mA
= 0.15W
IN
Thermal Resistance
=
®
– V
package.
⎝
⎛
OUT
T
®
J(MAX)
) I
OUT
JA
+ V
- T
Minimum Footprint
θ
JA
A
IN
Recommended
I
GND
100°C/W
9
Substituting P
operating
operating conditions for the regulator circuit. The
junction-to-ambient
minimum footprint is 100°C/W.
The maximum power dissipation must not be
exceeded for proper operation.
For example, when operating the MIC5318-2.8YMT at
an input voltage of 3.3V and 300mA load with a
minimum footprint layout, the maximum ambient
operating temperature T
follows:
Therefore, a 2.8V application with 300mA of output
current can accept an ambient operating temperature
of 110°C in a 1.6mm x 1.6mm Thin MLF
For a full discussion of heat sinking and thermal
effects on voltage regulators, refer to the “Regulator
Thermals” section of Micrel’s Designing with Low-
Dropout Voltage Regulators handbook. This informa-
tion can be found on Micrel's website at:
http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
0.15W = (125°C – T
T
A
= 110°C
temperature
D
for P
D(max)
thermal
A
and solving for the ambient
will
A
)/(100°C/W)
can be determined as
give
resistance
M9999-092810-B
the
®
maximum
package.
for
the