LP3855ES-ADJ/NOPB National Semiconductor, LP3855ES-ADJ/NOPB Datasheet - Page 13

• Manufacturer Part Number: LP3855ES-ADJ/NOPB
• Description: IC REG LDO 1.5A ADJ VOLT TO263-5
• Manufacturer: National Semiconductor

Specifications of LP3855ES-ADJ/NOPB

• Regulator Topology: Positive Adjustable
• Voltage - Output: Adjustable
• Voltage - Input: 2.5 ~ 7 V
• 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: *LP3855ES-ADJ; *LP3855ES-ADJ/NOPB; LP3855ES-ADJ

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 3. θ
of TO-263 package for different copper area sizes, using
JA
vs Copper (1 Ounce) Area for TO-263
package
Figure 3
shows a curve for the
20074332
13
value for θ
32°C/W.
Figure 4
TO-263 packages for different ambient temperatures, assum-
ing θ
125°C.
FIGURE 4. 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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