MAX9755 Maxim Integrated Products, MAX9755 Datasheet - Page 14

• Manufacturer Part Number: MAX9755
• Description: 2.6W Stereo Audio Power Amplifiers and DirectDrive Headphone Amplifiers
• Manufacturer: Maxim Integrated Products

2.6W Stereo Audio Power Amplifiers and
DirectDrive Headphone Amplifiers
Table 1. MAX9750 Maximum Gain Settings
Table 2. MAX9751 Gain Settings
The MAX9750 features an audible alert beep input
(BEEP) that accepts a mono system alert signal and
mixes it into the stereo audio path. When the amplitude
of V
frequency of the beep signal is greater than 300Hz, the
beep signal is mixed into the active audio path (speaker
or headphone). If the signal at V
<800mV
the audio path. The amplitude of the BEEP signal at the
device output is roughly the amplitude of V
times the gain of the selected signal path.
The input resistor (R
amplifier, and thus the amplitude of V
R
where R
resistor (47kΩ) and V
Note that the BEEP amplifier can be set up as either an
attenuator, if the original alert signal amplitude is too
large, or set to gain up the alert signal if it is below
800mV
the value of the coupling capacitor as described in the
Input Filtering section. Multiple beep inputs can be
summed (Figure 8).
14
B
GAIN1
based on:
BEEP(OUT)
0
0
1
1
______________________________________________________________________________________
GAIN
P-P
0
1
P-P
INT
. AC couple the alert signal to BEEP. Choose
or <300Hz, the BEEP signal is not mixed into
is the value of the BEEP amplifier feedback
GAIN2
0
1
0
1
exceeds 800mV
R
SPEAKER MODE
B
B
GAIN (dB)
) sets the gain of the BEEP input
≤
IN
10.5
MAX9750A
V
is the BEEP input amplitude.
9
IN
10.5
13.5
12
×
0 8
9
.
P-P
R
INT
SPEAKER MODE GAIN (dB)
BEEP(OUT)
(Figure 8) and the
BEEP(OUT)
MODE GAIN (dB)
HEADPHONE
BEEP Input
MAX9750B
BEEP(OUT)
3
0
16.5
19.5
. Choose
15
18
is either
The MAX9751 features a 2:1 input multiplexer on each
amplifier, allowing input selection between two stereo
sources. The logic input IN1/2 controls both multiplex-
ers. A logic high selects input IN_1 and a logic low
selects input IN_2.
The MAX9750/MAX9751/MAX9755 features a 0.2µA,
low-power shutdown mode that reduces quiescent cur-
rent consumption and extends battery life. Driving
SHDN low disables the drive amplifiers, bias circuitry,
and charge pump, and drives BIAS and all outputs to
GND. Connect SHDN to V
The MAX9750/MAX9751/MAX9755 speaker amplifiers
feature Maxim’s comprehensive, industry-leading click-
and-pop suppression. During startup, the click-pop
suppression circuitry eliminates any audible transient
sources internal to the device. When entering shut-
down, both amplifier outputs ramp to GND quickly and
simultaneously.
MAX9750C
Figure 6. Volume Control Circuit
10.5
7.5
6
9
V
REF
DAC
HEADPHONE MODE GAIN (dB)
Click-and-Pop Suppression
DD
HPV
VOL
DD
for normal operation.
MAX9750
Input Multiplexer
www.DataSheet4U.com
0
0
3
3
Speaker Amplifier
Shutdown