SA58672 NXP Semiconductors, SA58672 Datasheet - Page 16

• Manufacturer Part Number: SA58672
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SA58672_4
Product data sheet
11.7 Efficiency and thermal considerations
11.8 Additional thermal information
For applications in which there are circuits that are EMI sensitive to low frequency
(< 1 MHz) and there are long leads from amplifier to speaker, it may be necessary to use
an LC output filter.
The maximum ambient operating temperature depends on the heat transferring ability of
the heat spreader on the PCB layout. In
power derating factor is given as 10 mW/K. The device thermal resistance, R
reciprocal of the power derating factor. Convert the power derating factor to R
Equation
For a maximum allowable junction temperature, T
maximum device dissipation of 0.84 W (420 mW per channel) and for 1.7 W per channel
output power, 4
Equation
The maximum ambient temperature is 66 C at maximum power dissipation for 5 V supply
and 4
protection circuitry turns the device off; this prevents damage to the IC. Using speakers
greater than 4
the output load current and increasing amplifier efficiency.
The SA58672 9 bump WLCSP package ground bumps are soldered directly to the PCB
heat spreader. By the use of thermal vias, the bumps may be soldered directly to a ground
plane or special heat sinking layer designed into the PCB. The thickness and area of the
heat spreader may be maximized to optimize heat transfer and achieve lower package
thermal resistance.
The SA58672 HVSON10 package has an exposed Die Attach Paddle (DAP), which is
soldered directly to the PCB heat spreader to provide enhanced heat transfer and achieve
lowest package thermal resistance.
R
T
th j-a
amb max
=
load. If the junction temperature of the SA58672 rises above 150 C, the thermal
4:
5:
----------------------------------------- -
derating factor
=
T
j max
further enhances thermal performance and battery lifetime by reducing
1
load, 5 V supply, the maximum ambient temperature is calculated using
–
R
Rev. 04 — 8 June 2009
th j-a
=
--------- -
0.01
1
P
max
=
100 K /W
=
Table 3 “Limiting
150
–
100 0.84
j
= 150 C and R
3.0 W mono class-D audio amplifier
values”, power dissipation, the
=
66 C
th(j-a)
SA58672
© NXP B.V. 2009. All rights reserved.
= 100 K/W and a
th(j-a)
th(j-a)
is the
by
16 of 27
(4)
(5)