ATA5278 ATMEL Corporation, ATA5278 Datasheet - Page 25

• Manufacturer Part Number: ATA5278
• Description: Stand-alone Antenna Driver
• Manufacturer: ATMEL Corporation

4832D–RKE–12/07
Figure 3-18. Operation Cycle Duration versus Power Dissipation
Note that the upper limit of this diagram (0.6s) is not a design parameter but just for representa-
tion reasons. The graphs continue to increase beyond the top line. For this diagram, following
parameters have been taken:
The thermal resistance R
everything behind (i.e., the thermal resistance between the solder pad and ambient and the ther-
mal capacitance of the copper layer(s)) depend only on the PCB design.
• The total thermal resistance is 35 K/W, composed of 10 K/W for the junction-to-case
• For the thermal capacitances, the package with an equivalent capacitance of approximately
• The thermal shutdown of the chip triggers at 150°C junction temperature
resistance R
copper-to-ambient resistance R
15 mJ/K and one PCB copper layer with dimensions of 50 mm
resulting in 0.426 J/K have been taken
th,jc
, 5 K/W for the case-to-copper resistance R
0.6
0.5
0.4
0.3
0.2
0.1
th,jc
0
1.5
and the thermal capacitance of the package are fixed values, but
Ta = 105
2.5
th,pcba
˚
C
Power Dissipation (W)
3.5
4.5
Ta = 85
5.5
˚
C
th,cpcb
6.5
and 20 K/W for the
50 mm
7.5
0.05 mm,
ATA5278
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