AD8016
EXPERIMENTAL RESULTS
35
30
25
20
The experimental data suggests that for both packages, and a
PCB as small as 4.7 square inches, reasonable junction tempera-
tures can be maintained even in the absence of air flow. The graph
in Figure 42 shows junction temperature versus air flow for various
dimensions of 1 ounce copper PCBs at an ambient temperature
of 24°C in both the ARB and ARP packages. For the worst case
package, the AD8016ARB and the worst case PCB at 4.7 square
inches, the extrapolated junction temperature for an ambient
environment of 85°C would be approximately 132°C with 0 LFM
of air flow. If the target maximum junction temperature of the
AD8016ARB is 125°C, a 4-layer PCB with 1 oz. copper covering
the outer layers and measuring 9 square inches is required
with 0 LFM of air flow.
ARB 0 LFM
ARB 50 LFM
ARB 100 LFM
ARB 150 LFM
ARB 200 LFM
ARP 0 LFM
ARP 50 LFM
ARP 100 LFM
15
10
ARP 150 LFM
ARP 200 LFM
4
7
10
PCB AREA – SQ-IN
Note that the AD8016ARE is targeted at xDSL applications
other than full-rate CO ADSL. The AD8016ARE is targeted at
g.lite and other xDSL applications where reduced power dissi-
pation can be achieved through a reduction in output power.
Extreme temperatures associated with full-rate ADSL using the
AD8016ARE should be avoided whenever possible.
Figure 43. Junction-to-Ambient Thermal Resistance vs.
PCB Area
50
45
40
75
ARB 4.7 SQ-IN
+24؇C AMBIENT
ARB 6 SQ-IN
70
65
60
55
50
45
40
35
30
25
ARE 0 LFM
ARB 7.125 SQ-IN
ARE 200 LFM
ARB 9 SQ-IN
ARP 4.7 SQ-IN
ARE 400 LFM
20
15
ARP 6 SQ-IN
10
0
ARP 9 SQ-IN
1
2
3
4
5
6
7
8
9
10
ARP 12 SQ-IN
100
PCB AREA – SQ-IN
0
50
150
200
Figure 44. Junction-to-Ambient Thermal Resistance vs.
PCB Area
AIR FLOW – LFM
Figure 42. Junction Temperature vs. Air Flow
REV. A
–15–
ADI [ ADI ]
