MAX9729ETI+T Maxim Integrated Products, MAX9729ETI+T Datasheet - Page 17

• Manufacturer Part Number: MAX9729ETI+T
• Description: IC AMP AUDIO .052W STER 28TQFN
• Manufacturer: Maxim Integrated Products
• Series: DirectDrive™r
• Type: Class ABr

Specifications of MAX9729ETI+T

• Output Type: Headphones, 2-Channel (Stereo)
• Max Output Power X Channels @ Load: 52mW x 2 @ 32 Ohm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Features: Bass Boost, Depop, I²C, Input Multiplexer, Short-Circuit and Thermal Protection, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 4. Multiplexer/Mixer Control (Register 0x00)
The MAX9729 features internal power-on reset (POR)
circuitry that initializes the device upon power-up. The
contents of the MAX9729’s command registers at
power-on are shown in Table 9.
Linear power amplifiers can dissipate a significant
amount of power under normal operating conditions.
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
and
specified in the Absolute Maximum Ratings section. For
example,
If the power dissipation exceeds the rated package
dissipation, reduce V
decrease the ambient temperature, or add heatsinking.
Large output, supply, and ground traces decrease
allowing more heat to be transferred from the package
to surrounding air.
Dynamic range is the difference between the noise
floor of the system and the output level at 1% THD+N. It
is essential that a system’s dynamic range be known
before setting the maximum output gain. Output clip-
ping will occur if the output signal is greater than the
dynamic range of the system. The DirectDrive architec-
ture of the MAX9729 has increased dynamic range (for
a given V
fiers. Due to the absolute maximum ratings of the
MAX9729 and to limit power dissipation, the MAX9729
includes internal circuitry that limits the output voltage
to approximately ±2.5V.
B6
0
0
1
1
θ
JA
J(MAX)
is the reciprocal of the derating factor in °C/W as
Power Dissipation and Heat Sinking
θ
DD
Stereo Headphone Amplifier with BassMax,
JA
) compared to other single-supply ampli-
B5
for the thin QFN package is +35°C/W.
0
1
0
1
is +150°C, T
Applications Information
P
D MAX
______________________________________________________________________________________
(
DD
)
=
, increase load impedance,
Output Dynamic Range
T
A
J MAX
(
is the ambient temperature,
(INL1 + INL2 + INL3) x A
θ
JA
)
−
INL1 x A
INL2 x A
INL3 x A
T
A
Power-On Reset
OUTL
Volume Control, and Input Mux
V_TOTAL
V_TOTAL
V_TOTAL
V_TOTAL
θ
JA
,
Use the THD+N vs. Output Power graph in the Typical
Operating Characteristics to identify the system’s
dynamic range. Find the output power that causes 1%
THD+N for a given load. This point will indicate what
output power causes the output to begin to clip. Use
the following equation to determine the peak-to-peak
output voltage that causes 1% THD+N for a given load:
where P
THD+N, R
peak-to-peak output voltage. Determine the total volt-
age gain (A
voltage based on the maximum peak-to-peak input
voltage (V
The A
voltage gain setting, volume setting, and bass boost
gain if BassMax is enabled (see the Maximum Gain
Control, Volume Control, and BassMax Gain-Setting
Components sections).
The MAX9729 features an undervoltage lockout (UVLO)
function that prevents the device from operating if the
supply voltage is less than 1.65V. This feature ensures
proper operation during brownout conditions and pre-
vents deep battery discharge. Once the supply voltage
exceeds the UVLO threshold, the MAX9729 charge
pump is turned on, the amplifiers are powered (provid-
ed that SHDN is high), and the command registers are
reset to their POR values (see Table 9).
Use ceramic capacitors with a low ESR for optimum perfor-
mance. For optimal performance over the extended tem-
perature range, select capacitors with an X7R dielectric.
V_TOTAL
OUT_1%
IN_(P-P)
L
V
is the load resistance, and V
OUT P P
V_TOTAL
setting is determined by the maximum
(INR1 + INR2 + INR3) x A
A
_(
):
is the output power that causes 1%
V TOTAL
Charge-Pump Capacitor Selection
−
_
) necessary to attain this output
)
=
INR1 x A
INR2 x A
INR3 x A
2 2
=
Component Selection
OUTR
(
P
V
OUT
OUT P P
V
V_TOTAL
V_TOTAL
V_TOTAL
IN P P
_(
_ %
_(
1
−
−
V_TOTAL
)
×
)
OUT_(P-P)
R
L
)
UVLO
is the
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