MAX9755 Maxim Integrated Products, MAX9755 Datasheet - Page 18

• 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
Figure 7a. Volume Control Transfer Function
Figure 7c. Volume Control Transfer Function
Figure 8. Beep Input
18
______________________________________________________________________________________
-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
0
VOLUME CONTROL TRANSFER FUNCTION
0
HEADPHONE MODE
0.5
0.5
HEADPHONE MODE
1.0
1.0
SOURCE 1
SOURCE 2
SOURCE 3
1.5
MAX9750C
1.5
MAX9750A
V
V
VOL
VOL
2.0
2.0
(V)
SPEAKER MODE
(V)
0.47µF
0.47µF
0.47µF
SPEAKER MODE
GAIN1 = GAIN2 = 0
2.5
GAIN1 = GAIN2 = 0
2.5
3.0
3.0
47kΩ
47kΩ
47kΩ
R
R
R
S1
S2
S3
AUDIO
TAPER
AUDIO
TAPER
3.5
3.5
4.0
4.0
BEEP
BIAS
47kΩ
R
INT
(0.3V
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 Power-Up/Down Waveform in the Typical
Operating Characteristics shows that there are minimal
spectral components in the audible range at the output
upon startup and shutdown.
Figure 7b. Volume Control Transfer Function
(300Hz THRESHOLD)
FREQUENCY
V
P-P
DETECTOR
DETECTOR
OUT(BEEP)
WINDOW
THRESHOLD)
-10
-20
-30
-40
-50
-60
-70
-80
20
10
0
VOLUME CONTROL TRANSFER FUNCTION
0
0.5
HEADPHONE MODE
SPEAKER/HEADPHONE
AMPLIFER INPUTS
MAX9750
1.0
1.5
MAX9750B
V
VOL
2.0
SPEAKER MODE
(V)
GAIN1 = GAIN2 = 0
2.5
Headphone Amplifier
www.DataSheet4U.com
3.0
AUDIO
TAPER
3.5
4.0