DS3717 Rev 12

13/22

L4979D-E, L4979MD

Package and PCB thermal data

21

4

Package and PCB thermal data

4.1

SO-8 thermal data

Figure 5. SO-8 PC board

Note:

Layout condition of Rth and Zth measurements (PCB: FR4 area = 58 mm x 58 mm, PCB

thickness = 2 mm, Cu thickness = 35 mm, Copper areas: from minimum pad lay-out to

2cm2).

Figure 6. Rthj-amb vs PCB copper area in open box free air condition

GAPGCFT00158

110

120

130

140

150

160

170

0

0.5

1

1.5

2

2.5

PCB Cu heatsink area (cm^2)

RTHj_amb vs Cu heatsink area

RTHjamb

GAPGCFT00208