STA559BWQS13TR STMICROELECTRONICS [STMicroelectronics], STA559BWQS13TR Datasheet - Page 61

• Manufacturer Part Number: STA559BWQS13TR
• Description: 5-V, 2-A, 2.1-channel high-efficiency digital audio system with QSound QHD
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STA559BWQS
7
Package thermal characteristics
Due to the high efficiency of the system the dissipated power is negligible, allowing the use
of the STA559BWQS without heat sink but using only a small copper area on the PCB.
Using a double layer PCB the thermal resistance junction to ambient with two copper ground
areas of 3 x 3 cm
The dissipated power within the device depends primarily on the supply voltage, load
impedance and output modulation level.
The max estimated dissipated power for the STA559BWQS is:
2 x 3 W into 4 Ω at 5 V
2 x 0.7 W + 1 x 3 W into 4 Ω at 5 V
2 x 1.4 W + 1 x 6 W into 2 Ω at 5 V
This gives, with the suggested board copper area, a max ∆Tj of only approximately 20° C for
the worst case of the above mentioned applications. The safety margin before the thermal
protection intervention (Tj=150°C) is thus ensured, also in severe environments where the
ambient temperature exceeds 50° C.
Figure 36. Double layer PCB with copper ground area and with 16 via holes
Figure 37
two different sizes of copper layers.
Figure 37. PowerSSO-36 power derating curve
shows the power derating curves for the PowerSSO-36 package on a board with
Pd (W)
2
and with 16 via holes (see
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
0
0
Copper Area 2x2 cm
and via holes
20
20
40
40
Copper Area 3x3 cm
and via holes
Pd max ~ 600mW
Pd max < 500mW
Pd max ~ 800mW
60
60
Figure
Tamb ( °C)
80
80
36) is 24° C/W in natural air convection.
100
100
Package thermal characteristics
STA559BWQS
PowerSSO-36
120
120
STA335BW
PSSO36
140
140
160
160
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