MAX9729ETI+T Maxim Integrated Products, MAX9729ETI+T Datasheet - Page 10

• 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

The MAX9729 stereo headphone amplifier features
Maxim’s DirectDrive architecture, eliminating the large
output-coupling capacitors required by conventional
single-supply headphone amplifiers. The MAX9729
consists of two 52mW Class AB headphone amplifiers,
3:1 stereo input multiplexer/mixer, two adjustable gain
preamplifiers, a dedicated beep amplifier with indepen-
dent gain control, hardware/software shutdown control,
inverting charge pump, integrated 32-level volume con-
trol, BassMax circuitry, comprehensive click-and-pop
suppression circuitry, and an I
interface (see the Functional Diagram/Typical
Operating Circuit ). A negative power supply (PV
created internally by inverting the positive supply
(PV
increases the dynamic range of the amplifiers to almost
twice that of other single-supply amplifiers, increasing
the total available output power.
An I
munication between the MAX9729 and a microcon-
Stereo Headphone Amplifier with BassMax,
Volume Control, and Input Mux
10
DD
PIN
2
16
17
18
19
20
21
23
24
25
26
27
28
EP
______________________________________________________________________________________
C/SMBus-compatible interface allows serial com-
). Powering the amplifiers from V
BEEP_EN
NAME
SHDN
OUTR
OUTL
BEEP
BMR
INR1
BML
INL1
INL2
INL3
V
EP
DD
Detailed Description
Right BassMax Input. Connect an external passive network between OUTR and BMR to apply bass
boost to the right-channel output. See the BassMax Gain-Setting Components section. Connect BMR to
SGND if BassMax is not used.
Right Headphone Output
Left Headphone Output
Left BassMax Input. Connect an external passive network between OUTL and BML to apply bass boost
to the left-channel output. See the BassMax Gain-Setting Components section. Connect BML to SGND,
if BassMax is not used.
Beep Enable Input. Connect BEEP_EN to PV
beep amplifier.
Active-Low Shutdown Input. Drive SHDN low to disable the MAX9729. Connect SHDN to V
in command register 0x00 is equal to 1 for normal operation (see Command Registers section).
Power-Supply Input. Bypass V
are internally connected and should each have a 1µF bypass capacitor located as to close to the
device as possible.
Beep Input
Left-Channel Input 1
Left-Channel Input 2
Left-Channel Input 3
Right-Channel Input 1
Exposed Paddle. Connect EP to SV
2
C/SMBus-compatible
DD
and PV
DD
SS
) is
to PGND with a 1µF capacitor and connect to PV
SS
SS
or leave unconnected.
troller. The MAX9729’s slave address is programmed to
one of two different values using the ADD input allowing
two MAX9729 ICs to share the same bus (see Table 1).
The internal command registers control the shutdown
mode of the MAX9729, select/mix input signal sources,
enable the BassMax circuitry, headphone and beep
amplifier gains, and set the volume level (see Table 2).
The MAX9729’s BassMax circuitry improves audio
reproduction by boosting the bass response of the
amplifier, compensating for any low-frequency attenua-
tion introduced by the headphone. External compo-
nents set the MAX9729’s overall gain allowing for
custom gain settings (see the BassMax Gain-Setting
Components section).
Traditional single-supply headphone amplifiers have
their outputs biased about a nominal DC voltage, typi-
cally half the supply, for maximum dynamic range.
Large coupling capacitors are needed to block this DC
bias from the headphone. Without these capacitors, a
significant amount of DC current flows to the head-
DD
FUNCTION
to enable the beep amplifier or to PGND to disable the
Pin Description (continued)
DD
. V
DD
DD
DirectDrive
and PV
while B7
DD