LM78 datasheet(3/28 Pages) TI

3 / 28 page

LM340-N, LM78xx

www.ti.com

SNOSBT0I – FEBRUARY 2000 – REVISED MARCH 2013

Operating Conditions

(1) (continued)

LM140

−55°C to +125°C

Temperature Range (TA)

(2)

LM340A, LM340-N

0°C to +125°C

LM7808C

0°C to +125°C

(2)

The maximum allowable power dissipation at any ambient temperature is a function of the maximum junction temperature for operation

(TJMAX = 125°C or 150°C), the junction-to-ambient thermal resistance (θJA), and the ambient temperature (TA). PDMAX = (TJMAX −

TA)/θJA. If this dissipation is exceeded, the die temperature will rise above TJMAX and the electrical specifications do not apply. If the die

temperature rises above 150°C, the device will go into thermal shutdown. For the TO-3 package (NDS), the junction-to-ambient thermal

resistance (

θJA) is 39°C/W. When using a heatsink, θJA is the sum of the 4°C/W junction-to-case thermal resistance (θJC) of the TO-3

package and the case-to-ambient thermal resistance of the heatsink. For the TO-220 package (NDE),

θJA is 54°C/W and θJC is 4°C/W. If

SOT-223 is used, the junction-to-ambient thermal resistance is 174°C/W and can be reduced by a heatsink (see Applications Hints on

heatsinking).If the DDPAK\TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area

thermally connected to the package: Using 0.5 square inches of copper area,

θJA is 50°C/W; with 1 square inch of copper area, θJAis

37°C/W; and with 1.6 or more inches of copper area,

θJA is 32°C/W.

Submit Documentation Feedback

Product Folder Links: LM340-N LM78xx

LM78 Datasheet(PDF) 3 Page - Texas Instruments