LM4952TSBD National Semiconductor, LM4952TSBD Datasheet - Page 12

• Manufacturer Part Number: LM4952TSBD
• Description: BOARD EVALUATION LM4952TS
• Manufacturer: National Semiconductor
• Series: Boomer®r

Specifications of LM4952TSBD

• Amplifier Type: Class AB
• Output Type: 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 3.8W x 2 @ 4 Ohm
• Voltage - Supply: 9.6 V ~ 16 V
• Operating Temperature: -40°C ~ 85°C
• Board Type: Fully Populated
• Utilized Ic / Part: LM4952
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

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Application Information
HIGH VOLTAGE BOOMER WITH INCREASED OUTPUT
POWER
Unlike previous 5V Boomer
signed to operate over a power supply voltages range of
9.6V to 16V. Operating on a 12V power supply, the LM4952
will deliver 3.8W into a 4Ω SE load with no more than 10%
THD+N.
POWER DISSIPATION
Power dissipation is a major concern when designing a
successful single-ended or bridged amplifier. Equation (2)
states the maximum power dissipation point for a single-
ended amplifier operating at a given supply voltage and
driving a specified output load.
The LM4952’s dissipation is twice the value given by Equa-
tion (2) when driving two SE loads. For a 12V supply and two
4Ω SE loads, the LM4952’s dissipation is 1.82W.
The maximum power dissipation point given by Equation (1)
must not exceed the power dissipation given by Equation
(2):
The LM4952’s T
LM4952’s θ
copper plane of at least 16in
P
DMAX-SE
JA
is 20˚C/W when the metal tab is soldered to a
P
= (V
DMAX
JMAX
DD
’ = (T
= 150˚C. In the TS package, the
)
2
/ (2π
®
JMAX
2
amplifiers, the LM4952 is de-
. This plane can be split be-
2
R
- T
L
): Single Ended
A
FIGURE 2. Typical LM4952 SE Application Circuit
) / θ
JA
(1)
(2)
12
tween the top and bottom layers of a two-sided PCB. Con-
nect the two layers together under the tab with a 5x5 array of
vias. At any given ambient temperature T
to find the maximum internal power dissipation supported by
the IC packaging. Rearranging Equation (2) and substituting
P
the maximum ambient temperature that still allows maximum
stereo power dissipation without violating the LM4952’s
maximum junction temperature.
For a typical application with a 12V power supply and an SE
4Ω load, the maximum ambient temperature that allows
maximum stereo power dissipation without exceeding the
maximum junction temperature is approximately 77˚C for the
TS package.
Equation (4) gives the maximum junction temperature
T
maximum junction temperature by reducing the power sup-
ply voltage or increasing the load resistance. Further allow-
ance should be made for increased ambient temperatures.
The above examples assume that a device is operating
around the maximum power dissipation point. Since internal
JMAX
DMAX
. If the result violates the LM4952’s 150˚C, reduce the
for P
DMAX
T
JMAX
T
’ results in Equation (3). This equation gives
A
= T
= P
JMAX
DMAX-MONOBTL
- P
DMAX-SE
200809E8
θ
JA
θ
A
JA
, use Equation (2)
+ T
A
(3)
(4)