LP3855ESX-5.0/NOPB National Semiconductor, LP3855ESX-5.0/NOPB Datasheet - Page 15

• Manufacturer Part Number: LP3855ESX-5.0/NOPB
• Description: IC REG LDO 1.5A 5.0V TO-263-5
• Manufacturer: National Semiconductor

Specifications of LP3855ESX-5.0/NOPB

• Regulator Topology: Positive Fixed
• Voltage - Output: 5V
• Voltage - Input: Up to 7V
• Voltage - Dropout (typical): 0.24V @ 1.5A
• Number Of Regulators: 1
• Current - Output: 1.5A (Max)
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: TO-263-5, D²Pak (5 leads + Tab), TO-263BA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Limit (min): -
• Other names: LP3855ESX-5.0

HEATSINKING TO-263 PACKAGE
The TO-263 package uses the copper plane on the PCB as
a heatsink. The tab of these packages are soldered to the
copper plane for heat sinking.
θ
a typical PCB with 1 ounce copper and no solder mask over
the copper area for heat sinking.
As shown in the figure, increasing the copper area beyond 1
square inch produces very little improvement. The minimum
JA
FIGURE 5. θ
of TO-263 package for different copper area sizes, using
JA
vs Copper (1 Ounce) Area for TO-263
package
Figure 5
shows a curve for the
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15
value for θ
32°C/W.
Figure 6
TO-263 packages for different ambient temperatures, assum-
ing θ
125°C.
FIGURE 6. Maximum power dissipation vs ambient
JA
is 35°C/W and the maximum junction temperature is
shows the maximum allowable power dissipation for
JA
temperature for TO-263 package
for the TO-263 package mounted to a PCB is
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