MAX9751 Maxim Integrated Products, Inc., MAX9751 Datasheet - Page 19

• Manufacturer Part Number: MAX9751
• Description: 2.6w Stereo Audio Power Amplifiers And Directdrive Headphone Amplifiers
• Manufacturer: Maxim Integrated Products, Inc.

Figure 7a. Volume Control Transfer Function
Figure 7c. Volume Control Transfer Function
Figure 8. BEEP Input
-10
-20
-30
-40
-50
-60
-70
-80
-10
-20
-30
-40
-50
-60
-70
-80
20
10
20
10
0
0
VOLUME CONTROL TRANSFER FUNCTION
VOLUME CONTROL TRANSFER FUNCTION
0
0
2.6W Stereo Audio Power Amplifiers and
______________________________________________________________________________________
0.5
HEADPHONE MODE
0.5
HEADPHONE MODE
1.0
1.0
SOURCE 1
SOURCE 2
SOURCE 3
1.5
1.5
MAX9750A
MAX9750C
V
V
VOL
VOL
2.0
2.0
0.47μF
0.47μF
0.47μF
(V)
(V)
SPEAKER MODE
SPEAKER MODE
GAIN1 = GAIN2 = 0
2.5
2.5
GAIN1 = GAIN2 = 0
DirectDrive Headphone Amplifiers
47kΩ
47kΩ
47kΩ
R
R
R
B1
B2
B3
3.0
3.0
TAPER POT
TAPER POT
AUDIO
AUDIO
3.5
3.5
4.0
4.0
BEEP
BIAS
47kΩ
R
INT
(0.8V
(300Hz THRESHOLD)
In conventional single-supply headphone amplifiers,
the output-coupling capacitor is a major contributor of
audible clicks and pops. Upon startup, the amplifier
charges the coupling capacitor to its bias voltage, typi-
cally half the supply. Likewise, during shutdown, the
capacitor is discharged to GND. A DC shift across the
capacitor results, which in turn appears as an audible
transient at the speaker. Since the MAX9750/MAX9751/
MAX9755 do not require output-coupling capacitors, no
audible transient occurs.
Additionally, the MAX9750/MAX9751/MAX9755 features
extensive click-and-pop suppression that eliminates
any audible transient sources internal to the device.
The Turn-On Response (Headphone Mode) and Turn-
Off Response (Headphone Mode) graphs in the Typical
Operating Characteristics shows that there are minimal
transient components in the audible range at the output
upon startup and shutdown.
Figure 7b. Volume Control Transfer Function
V
P-P
FREQUENCY
DETECTOR
OUT(BEEP)
DETECTOR
WINDOW
THRESHOLD)
-10
-20
-30
-40
-50
-60
-70
-80
20
10
0
VOLUME CONTROL TRANSFER FUNCTION
0
SPEAKER/HEADPHONE
0.5
AMPLIFER INPUTS
MAX9750
HEADPHONE MODE
1.0
1.5
MAX9750B
V
VOL
2.0
SPEAKER MODE
(V)
Headphone Amplifier
GAIN1 = GAIN2 = 0
2.5
3.0
TAPER POT
AUDIO
3.5
4.0
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