ULN2064B, ULN2066B, ULN2068B, ULN2074B Mounting instructions
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6 Mounting instructions
The R
thJA
can be reduced by soldering the GND pins to a suitable copper area of the printed
circuit board (Figure 14) or to an external heatsink (Figure 15).
The diagram of Figure 16 shows the maximum dissipated power P
TOT
and the R
thJA
as a
function of the side "α" of two equal square copper areas having a thickness of 35 µ (1.4
mils).
During soldering the pins temperature must not exceed 260 °C and the soldering time must
not be longer than 12 seconds.
The external heatsink or printed circuit copper area must be connected to electrical ground.
Figure 14. Example of P.C. board area which is
used as heatsink
Figure 15. External heatsink mounting
example
Figure 16. Maximum dissipated power and
junction to ambient thermal
resistance vs. side "α"
Figure 17. Maximum allowable power
dissipation vs. ambient
temperature
