MAX4410EVKIT Maxim Integrated Products, MAX4410EVKIT Datasheet - Page 14

• Manufacturer Part Number: MAX4410EVKIT
• Description: Power Management Modules & Development Tools MAX4410 EVAL KIT MAX4410 EVAL KIT
• Manufacturer: Maxim Integrated Products

Specifications of MAX4410EVKIT

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

80mW, DirectDrive Stereo Headphone Driver
with Shutdown
The MAX4410 features two shutdown controls allowing
either channel to be shut down or muted independently.
SHDNL controls the left channel while SHDNR controls
the right channel. Driving either SHDN_ low disables the
respective channel, sets the driver output impedance to
about 1kΩ, and reduces the supply current to less than
10µA. When both SHDN_ inputs are driven low, the
charge pump is also disabled, further reducing supply
current draw to 6µA. The charge pump is enabled once
either SHDN_ input is driven high.
In traditional single-supply audio drivers, the output-
coupling capacitor is a major contributor of audible
clicks and pops. Upon startup, the driver charges the
coupling capacitor to its bias voltage, typically half the
supply. Likewise, on shutdown the capacitor is dis-
charged to GND. This results in a DC shift across the
capacitor, which in turn, appears as an audible transient
at the speaker. Since the MAX4410 does not require
output-coupling capacitors, this does not arise.
Additionally, the MAX4410 features extensive click-and-
pop suppression that eliminates any audible transient
sources internal to the device. The Power-Up/Down
Waveform in the Typical Operating Characteristics
shows that there are minimal spectral components in the
audible range at the output upon startup or shutdown.
In most applications, the output of the preamplifier dri-
ving the MAX4410 has a DC bias of typically half the
supply. At startup, the input-coupling capacitor is
charged to the preamplifier’s DC-bias voltage through
the R
the capacitor and an audible click/pop. Delaying the
rise of the MAX4410’s SHDN_ signals 4 to 5 time con-
stants (200ms to 300ms) based on R
to the start of the preamplifier eliminates this click/pop
caused by the input filter.
Under normal operating conditions, linear power ampli-
fiers 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:
where T
ture, and θ
14
______________________________________________________________________________________
F
of the MAX4410, resulting in a DC shift across
J(MAX)
JA
P
DISSPKG MAX
is the reciprocal of the derating factor in
Applications Information
is +150°C, T
Click-and-Pop Suppression
(
)
=
A
T
J MAX
is the ambient tempera-
(
Power Dissipation
θ
JA
)
IN
−
T
and C
A
Shutdown
IN
relative
°C/W as specified in the Absolute Maximum Ratings
section. For example, θ
+109.9°C/W.
The MAX4410 has two sources of power dissipation,
the charge pump and the two drivers. If the power dis-
sipation for a given application exceeds the maximum
allowed for a given package, either reduce V
increase load impedance, decrease the ambient tem-
perature, or add heat sinking to the device. Large out-
put, supply, and ground traces improve the maximum
power dissipation in the package.
Thermal overload protection limits total power dissipa-
tion in the MAX4410. When the junction temperature
exceeds +140°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.
The device has been specified for the worst-case sce-
nario— when both inputs are in phase. Under this con-
dition, the drivers simultaneously draw current from the
charge pump, leading to a slight loss in headroom of
V
right signals have differences in both magnitude and
phase, subsequently leading to an increase in the max-
imum attainable output power. Figure 4 shows the two
extreme cases for in and out of phase. In reality, the
available power lies between these extremes.
Figure 4. Output Power vs. Supply Voltage with Inputs In/Out
of Phase
SS
. In typical stereo audio applications, the left and
0.001
0.01
100
0.1
10
1
0
TOTAL HARMONIC DISTORTION PLUS
V
A
R
f
IN
DD
V
L
= 16Ω
= 10kHz
= -1V/V
OUTPUTS IN
PHASE
= 3V
NOISE vs. OUTPUT POWER
50
OUTPUT POWER (mW)
JA
of the TSSOP package is
100
ONE
CHANNEL
OUTPUTS
180° OUT OF
PHASE
150
Output Power
200
DD
,