max9702etit Maxim Integrated Products, Inc., max9702etit Datasheet - Page 23

• Manufacturer Part Number: max9702etit
• Description: Max9702 1.8w, Filterless, Stereo, Class D Audio Power Amplifier And Directdrive Stereo Headphone Amplifier
• Manufacturer: Maxim Integrated Products, Inc.

Amplifier and DirectDrive Stereo Headphone Amplifier
The MAX9702 has one command register that is used to
set speaker and headphone gain, select an input mode,
and enable/disable shutdown. Table 3 describes the
function of the bits contained in the command register.
The MAX9702 has eight internally set speaker gains
selected by B0–B2 (see Table 4).
The MAX9702 has four headphone gain settings select-
ed by B3 and B4 (see Table 5).
The MAX9702 features a multiplexer that selects
between the stereo and mono inputs. The mux also
Table 3. Command Bits and Description
Table 4. Programmable Speaker Gain
B2
BIT
0
0
0
0
1
1
1
1
B0
B1
B2
B3
B4
B5
B6
B7
Speaker gain-setting bit
Speaker gain-setting bit
Speaker gain-setting bit
Headphone gain-setting bit
Headphone gain-setting bit
MONO enable bit (0 = Mute)
STEREO enable bit (0 = Mute)
Shutdown bit (1 = normal, 0 =
shutdown)
B1
0
0
1
1
0
0
1
1
______________________________________________________________________________________
1.8W, Filterless, Stereo, Class D Audio Power
B0
FUNCTION
0
1
0
1
0
1
0
1
Programmable Headphone Gain
Programmable Speaker Gain
Programmable Input Modes
Speaker gain
Speaker gain
Speaker gain
Speaker gain
Speaker gain
Speaker gain
Speaker gain
Speaker gain
FUNCTION
Command Register
DEFAULT
0
0
1
1
0
0
1
1
GAIN
(dB)
+12
+15
+18
+21
+0
+3
+6
+9
acts as a mixer when the mono and stereo inputs are
enabled at the same time. The MUTE function disables
the input signal to the output. All modes are selected
through B5 and B6 (see Table 6).
The MIX function attenuates and mixes the MONO and
STEREO signals. Each input signal is attenuated by
6dB prior to being mixed. This attenuation preserves
headroom at the output. The output signal is represent-
ed by the following equation when in MIX mode:
where A
Table 5. Programmable Headphone Gain
Table 6. Programmable Input Modes
B6
B4
0
0
1
1
(
0
0
1
1
OUT
V
_ ( )
is the amplifier gain.
+
B5
0
1
0
1
−
B3
0
1
0
1
OUT
MUTE (no input on the output)
MONO (MONO input sent to the output)
STEREO (left and right inputs sent to the
outputs) (default)
MIX (MONO and STEREO inputs are
mixed and output)
_ _
Headphone gain
Headphone gain
(default)
Headphone gain
Headphone gain
)
or HP
FUNCTION
_
=
FUNCTION



IN
_
+
2
INM
GAIN (dB)

 ×

+1
+4
+7
-2
A
V
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