max9718aeubt Maxim Integrated Products, Inc., max9718aeubt Datasheet - Page 11

• Manufacturer Part Number: max9718aeubt
• Description: Low-cost, Mono/stereo, 1.4w Differential Audio Power Amplifiers
• Manufacturer: Maxim Integrated Products, Inc.

Under normal operating conditions, the MAX9718/
MAX9719 dissipate a significant amount of power. The
maximum power dissipation for each package is given
in the Absolute Maximum Ratings section under
Continuous Power Dissipation or can be calculated by
the following equation:
where T
ture, and θ
°C/W as specified in the Absolute Maximum Ratings
section. For example, θ
+59.2°C/W.
The increase in power delivered by the BTL configura-
tion directly results in an increase in internal power dis-
sipation over the single-ended configuration. The
maximum internal power dissipation for a given V
and load is given by the following equation:
If the internal power dissipation for a given application
exceeds the maximum allowed for a given package,
reduce power dissipation by increasing the ground
plane heat-sinking capability and the size of the traces
to the device (see the Layout and Grounding section).
Other methods for reducing power dissipation are to
reduce V
ent temperature, reduce gain, or reduce input signal.
Thermal-overload protection limits total power dissipa-
tion in the MAX9718/MAX9719. When the junction tem-
perature exceeds +160°C, the thermal protection
circuitry disables the amplifier output stage. The ampli-
fiers are enabled once the junction temperature cools
Figure 1. Bridge-Tied Load Configuration
J(MAX)
CC
Power Dissipation and Heat Sinking
JA
, increase load impedance, decrease ambi-
is the reciprocal of the derating factor in
is +150°C, T
P
D MAX
1.4W Differential Audio Power Amplifiers
P
______________________________________________________________________________________
+1
-1
(
D MAX
(
)
=
)
JA
=
T
J MAX
2
(
A
π
of the TQFN package is
V
2
CC
θ
is the ambient tempera-
R
JA
L
)
2
−
T
A
V
2 x V
V
OUT(P-P)
OUT(P-P)
OUT(P-P)
CC
Low-Cost, Mono/Stereo,
by 15°C. A pulsing output under continuous thermal
overload results as the device heats and cools.
For optimum power dissipation and heat sinking, con-
nect the exposed pad found on the µMAX, TDFN,
TQFN, and TSSOP packages to a large ground plane.
The MAX9718B/E, MAX9718C/F, MAX9718D/G,
MAX9719B, MAX9719C, and MAX9719D feature inter-
nally fixed gains (see the Selector Guide). This simpli-
fies design, decreases required footprint size, and
eliminates external gain-setting resistors. Resistors R1
and R2 shown in the Typical Operating Circuit are used
to achieve each fixed gain.
External feedback resistors set the gain of the
MAX9718A/H and MAX9719A. Resistors R
(Figure 2) set the gain of the amplifier as follows:
where A
10kΩ and an R
R
digitally controlled potentiometer to alter the gain under
software control.
Figure 2. Setting the MAX9718A/H/MAX9719A Gain
NONINVERTING
F
DIFFERENTIAL
DIFFERENTIAL
can be either fixed or variable, allowing the use of a
INVERTING
INPUT
INPUT (OPTIONAL)
V
(OPTIONAL)
is the desired voltage gain. Hence, an R
F
R
of 20kΩ yields a gain of 2V/V, or 6dB.
R
IN
IN
Adjustable Differential Gain
A
V
IN-
IN+
Fixed Differential Gain
=
MAX9718A/H
GENERATOR
MAX9719A
R
R
R
BIAS
F
IN
F
Gain-Setting Resistors
R
F
OUT+
OUT-
F
and R
IN
11
IN
of