max9752aetit Maxim Integrated Products, Inc., max9752aetit Datasheet - Page 16

• Manufacturer Part Number: max9752aetit
• Description: 2.2w, Low-emi, Stereo, Class D Power Amplifiers With Directdrive Headphone Amplifiers
• Manufacturer: Maxim Integrated Products, Inc.

Table 2 shows the amplifier gain settings needed to
attain maximum speaker output power from a given
input voltage and load.
The gain of the MAX9753/MAX9754 is set by GAIN.
Drive GAIN high to set the gain of the speaker ampli-
fiers to 9dB, and the gain of the headphone amplifiers
to 0dB. Drive GAIN low to set the gain of the speaker
amplifiers to 10.5dB, and the gain of the headphone
amplifiers to 3dB (Table 3).
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Table 2. MAX9752 Speaker Amplifier Gain
Settings for Maximum Output Power
16
MAX9752A
MAX9752B
MAX9752C
GAIN
______________________________________________________________________________________
(dB)
10.5
12.0
13.5
10.5
12.0
13.5
15.0
16.5
18.0
19.5
15.0
16.5
18.0
19.5
10.5
10.5
9.0
9.0
6.0
7.5
9.0
6.0
7.5
9.0
(V
INPUT
1.004
0.844
0.710
0.598
1.099
0.925
0.778
0.655
0.503
0.423
0.356
0.300
0.551
0.464
0.390
0.328
1.418
1.193
1.004
0.844
1.553
1.307
1.099
0.925
RMS
)
(Ω)
R
4
4
4
4
8
8
8
8
4
4
4
4
8
8
8
8
4
4
4
4
8
8
8
8
MAX9753/MAX9754
L
P
(W)
2.0
2.0
2.0
2.0
1.2
1.2
1.2
1.2
2.0
2.0
2.0
2.0
1.2
1.2
1.2
1.2
2.0
2.0
2.0
2.0
1.2
1.2
1.2
1.2
OUT
Table 4 shows the amplifier input voltage needed to
attain maximum speaker output power from a given
gain setting and load.
The MAX9752 features an analog volume control that
varies the speaker and headphone amplifier’s gain in 31
discrete steps based upon the DC voltage applied to
VOL. The input range of VOL is from 0 (full volume) to
0.858 x HPV
in Table 5. Control VOL with either a DAC or potentiome-
ter as shown in Figure 9. Because the VOL input is high
impedance (typically 100MΩ), it can also be driven with
an RC-filtered PWM signal. Connect the reference of the
DAC or potentiometer to HPV
trol is ratiometric to HPV
negated. The gain step sizes are not constant, the step
sizes at the upper extreme are 0.5dB/step, 2.0dB/step in
the midrange, and 4.0dB/step at the lower extreme.
Figure 10 shows the transfer function of the volume con-
trol for HPV
Table 3. MAX9753/MAX9754 Maximum
Gain Settings
Table 4. MAX9753/MAX9754 Input Voltage
and Gain Settings for Maximum Output
Power
GAIN
Analog Volume Control (VOL, MAX9752)
GAIN
(dB)
0
1
10.5
10.5
9.0
9.0
DD
DD
= 3.3V.
SPEAKER MODE
(full mute). Example step sizes are shown
(V
GAIN (dB)
INPUT
0.844
1.004
0.925
1.099
RMS
10.5
9.0
)
DD
, any changes in HPV
DD
. Since the volume con-
(Ω)
R
4
4
8
8
L
HEADPHONE MODE
GAIN (dB)
3
0
P
(W)
2.0
2.0
1.2
1.2
OUT
DD
are