max9723aebe Maxim Integrated Products, Inc., max9723aebe Datasheet - Page 13

• Manufacturer Part Number: max9723aebe
• Description: Max9723 Stereo Directdrive Headphone Amplifier With Bassmax, Volume Control, And I?c
• Manufacturer: Maxim Integrated Products, Inc.

data (see Figure 5). The MAX9723 pulls down SDA dur-
ing the master-generated 9th clock pulse. The SDA line
must remain stable and low during the high period of
the acknowledge clock pulse. Monitoring ACK allows
for detection of unsuccessful data transfers. An unsuc-
cessful data transfer occurs if a receiving device is
busy or if a system fault has occurred. In the event of
an unsuccessful data transfer, the bus master may
reattempt communication.
A write to the MAX9723 includes transmission of a
START condition, the slave address with the R/W bit
reset to 0 (see Table 1), one byte of data to configure
the command register, and a STOP condition. Figure 6
illustrates the proper format for one frame.
The MAX9723 only accepts write data, but it acknowl-
edges the receipt of its address byte with the R/W bit
set high. The MAX9723 does not write to the SDA bus
in the event that the R/W bit is set high. Subsequently,
Figure 4. START, STOP, and REPEATED START Conditions
Table 1. MAX9723 Address Map
Table 2. MAX9723 Command Register
MAX9723C
MAX9723D
SHUTDOWN
MAX9723A
MAX9723B
SCL
SDA
PART
B7
S
A6
1
1
1
1
BassMax
ENABLE
B6
______________________________________________________________________________________
A5
Stereo DirectDrive Headphone Amplifier
0
0
0
0
with BassMax, Volume Control, and I
MAX9723 SLAVE ADDRESS
A4
MAXIMUM
0
0
0
0
GAIN
B5
Sr
A3
1
1
1
1
A2
B4 B3 B2 B1 B0
1
1
1
1
Write Data Format
A1
VOLUME
0
0
0
0
P
A0
0
1
0
1
R/W
0
0
0
0
the master reads all 1’s from the MAX9723. Always
reset the R/W bit to 0 to avoid this situation.
The MAX9723 has one command register that is used
to enable/disable shutdown, enable/disable BassMax,
and set the maximum gain and volume. Table 2
describes the function of the bits contained in the com-
mand register.
Reset B7 to 0 to shut down the MAX9723. The MAX9723
wakes up from shutdown when B7 is set to 1 provided
SHDN is high. SHDN must be high and B7 must be set to
1 for the MAX9723 to operate normally (see Table 3).
Set B6 to 1 to enable BassMax (see Table 4). The output
signal’s low-frequency response will be boosted accord-
ing to the external components connected between
OUT_ and BB_. See the BassMax Gain-Setting
Components section in the Applications Information sec-
tion for details on choosing the external components.
Figure 5. Acknowledge
Table 3. Shutdown Control,
Table 4. BassMax Control
SCL
SDA
CONDITION
START
MAX9723 Disabled
MAX9723 Enabled
BassMax Disabled
BassMax Enabled
MODE
MODE
1
2
NOT ACKNOWLEDGE
ACKNOWLEDGE
Command Register
8
ACKNOWLEDGMENT
CLOCK PULSE FOR
SHDN = 1
B7
0
1
B6
0
1
9
2
C
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