MAX9766ETJ+ Maxim Integrated Products, MAX9766ETJ+ Datasheet - Page 17

• Manufacturer Part Number: MAX9766ETJ+
• Description: IC AMP AUDIO .75W MONO AB 32TQFN
• Manufacturer: Maxim Integrated Products
• Type: Class ABr

Specifications of MAX9766ETJ+

• Output Type: 1-Channel (Mono) with Stereo Headphones
• Max Output Power X Channels @ Load: 750mW x 1 @ 4 Ohm; 65mW x 2 @ 16 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Depop, I²C, Input Multiplexer, Microphone, Mute, Short-Circuit and Thermal Protection, Shutdown
• Mounting Type: Surface Mount
• Package / Case: 32-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

selects input IN_1 and a logic high selects input IN_2.
Both right- and left-channel multiplexers are controlled
by the same input.
The input multiplexer can also be used to further
expand the number of gain options available from the
MAX9765/MAX9766. Connect the audio source to the
device through two different input resistors for multiple
gain configurations (Figure 1). Additionally, the input
multiplexer allows a speaker equalization network to be
switched into the speaker signal path. This is typically
useful in optimizing acoustic response from speakers
with small physical dimensions.
The mono MAX9766 incorporates a mixer/attenuator
(see the Functional Diagram). In speaker (mono) mode,
the mixer/attenuator combines the two stereo inputs
(INL_ and INR_) and attenuates the resultant signal by
a factor of 2. This allows for full reproduction of a stereo
signal through a single speaker while maintaining opti-
mum headroom. The resistor connected between
GAINM and OUTL+ sets the device gain in speaker
mode. This allows the speaker amplifier to have a dif-
ferent gain and feedback network from the headphone
amplifier.
The headphone sensing function can be disabled by
the HPS_D bit (MAX9765/MAX9766). HPS_D bit deter-
mines whether the device is in automatic-detection
mode, or fixed-mode operation.
When the MAX9765/MAX9766 are in automatic head-
phone-detection mode, the state of the headphone
sense input (HPS) determines the operating mode of
the device. A voltage on HPS less than 0.7
the device to speaker mode. A voltage greater than 0.9
✕
Figure 1. Using the Input Multiplexer for Gain Setting
V
DD
disables the inverting bridge amplifier (OUT_-),
AUDIO
INPUT
750mW Audio Amplifiers with Headphone Amp,
Headphone Sense Disable Input
Headphone Sense Input (HPS)
______________________________________________________________________________________
15kΩ
30kΩ
IN_1
IN_2
Microphone Preamp, and Input Mux
MAX9765
Mono Mode
✕
V
DD
sets
which mutes the speaker amplifier and sets the device
into headphone mode.
Connect HPS to the control pin of a 3-wire headphone
jack as shown in Figure 2. With no headphone present,
the resistive voltage-divider created by R1 and R2 sets
the voltage on HPS to 44mV, setting the device to speak-
er mode. When a headphone plug is inserted into the
jack, the control pin is disconnected from the tip contact,
and HPS is pulled to V
into headphone mode. Place a resistor in series with the
control pin and HPS (R3) to prevent any audio signal
from coupling into HPS when the device is in speaker
mode.
The MAX9765/MAX9766/MAX9767 feature a 5µA, low-
power shutdown mode that reduces quiescent current
consumption and extends battery life. The drive and
microphone amplifiers and the bias circuitry are dis-
abled, the amplifier outputs (OUT_/MIC_) go high
impedance, and BIAS and MICBIAS are driven to GND.
The digital section of the MAX9765/MAX9766 remains
active when the device is shut down through the inter-
face. A logic high on bit 0 of the SHDN register places
the MAX9765/MAX9766 in shutdown. A logic low
enables the device. A logic low on the SHDN input
places the devices into shutdown mode, disables the
interface, and resets the I
A logic high on SHDN enables the device. A logic high
on SHDN enables the devices.
All devices feature a mute mode. When the device is
muted, the input is disconnected from the amplifiers.
MUTE only affects the power amplifiers, and does not
shut down the device. The MAX9765/MAX9766 MUTE
mode is selected by writing to the MUTE register (see
Command Byte Definitions). The left and right channels
can be independently muted. The MAX9767 features
an active-high MUTE input that mutes both channels.
The MAX9767 microphone amplifier input configuration
is controlled by the INT/EXT input. A logic low In
INT/EXT selects internal (differential) microphone
mode. A logic high selects external (single-ended)
mode.
The MAX9765/MAX9766/MAX9767 feature Maxim’s
comprehensive click-and-pop suppression. During
startup and shutdown, the common-mode bias voltage
of the amplifiers is slowly ramped to and from the DC
bias point using an S-shaped waveform. In headphone
Click-and-Pop Suppression
DD
2
through R1, setting the device
C registers to a default state.
Shutdown
INT /EXT
MUTE
17