MAX9761EVKIT Maxim Integrated, MAX9761EVKIT Datasheet - Page 19

• Manufacturer Part Number: MAX9761EVKIT
• Description: Amplifier IC Development Tools
• Manufacturer: Maxim Integrated
• Series: MAX9760, MAX9761, MAX9762, MAX9763r

When the MAX9760/MAX9762 are configured to auto-
matically detect the presence of a headphone jack, the
device defaults to gain setting A when the device is in
speaker mode. When the MAX9762/MAX9763 are con-
figured as speaker amplifiers, the gain setting defaults
to the mono setting (GAINM).
The MAX9760–MAX9763 can be configured as single-
ended headphone amplifiers through software or by
sensing the presence of a headphone plug (HPS). In
headphone mode, the inverting output of the BTL
amplifier is disabled, muting the speaker. The gain is
1/2 that of the device in speaker mode, and the output
power is reduced by a factor of 4.
In headphone mode, the load must be capacitively
coupled to the device, blocking the DC bias voltage
from the load (see Typical Application Circuit).
Under normal operating conditions, the MAX9760–
MAX9763 can 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:
Table 6. Status Register Format
BIT
7
6
5
4
3
2
1
0
REGISTER ADDRESS
Power Dissipation and Heat Sinking
Single-Ended Headphone Amplifier
P
DISSPKG MAX
______________________________________________________________________________________
Stereo 3W Audio Power Amplifiers with
AMPR+
(
AMPL+
AMPR-
HPSTS
NAME
AMPL-
THRM
X
X
)
=
T
J MAX
(
θ
JA
)
−
Headphone Drive and Input Mux
T
A
Don’t Care
Don’t Care
VALUE
0
1
0
1
0
1
0
1
0
1
0
1
Device temperature below thermal limit
Device temperature exceeding thermal limit
OUTR- current below current limit
OUTR- current exceeding current limit
OUTR+ current below current limit
OUTR+ current exceeding current limit
OUTL- current below current limit
OUTL- current exceeding current limit
OUTL+ current below current limit
OUTL+ current exceeding current limit
Device in speaker mode
Device in headphone mode
where T
ture, and θ
°C/W as specified in the Absolute Maximum Ratings
section. For example, θ
+42°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 power dissipation for a given V
given by the following equation:
If the power dissipation for a given application exceeds
the maximum allowed for a given package, either reduce
V
temperature, or add heat sinking to the device. Large
output, supply, and ground PC board traces improve the
maximum power dissipation in the package.
Thermal overload protection limits total power dissipa-
tion in these devices. When the junction temperature
exceeds +160°C, the thermal protection circuitry dis-
ables the amplifier output stage. The amplifiers are
enabled once the junction temperature cools by 15°C.
This results in a pulsing output under continuous ther-
mal-overload conditions as the device heats and cools.
DD
, increase load impedance, decrease the ambient
J(MAX)
JA
0000 0000
is the reciprocal of the derating factor in
is +150°C, T
P
DISS MAX
DESCRIPTION
(
—
—
JA
)
=
A
of the QFN package is
2
is the ambient tempera-
π
V
2
DD
R
L
2
DD
and load is
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