max9726aetpt Maxim Integrated Products, Inc., max9726aetpt Datasheet - Page 14
max9726aetpt
Manufacturer Part Number
max9726aetpt
Description
Max9726 Directdrive, Headphone Amplifier With Bassmax, I?c, Volume And Gain Control
Manufacturer
Maxim Integrated Products, Inc.
Datasheet
1.MAX9726AETPT.pdf
(24 pages)
DirectDrive, Headphone Amplifier with
BassMax, I
Figure 6. Write Data Format Example
Figure 7. Volume-Control Transfer Function
Table 2. Command Register
Table 3. Shutdown Control, SHDN = V
14
CONDITION
Disabled
Enabled
Shutdown
START
ACKNOWLEDGE FROM MAX9726
COMMAND BYTE IS STORED ON
S
______________________________________________________________________________________
B7
RECEIPT OF STOP CONDITION
SLAVE ADDRESS
100
120
MODE
20
40
60
80
0
0
BassMax
Enable
R/W
B6
16
0
CODE (DECIMAL)
A
2
B7 B6 B5 B4 B3 B2
32
C, Volume and Gain Control
COMMAND BYTE
FROM MAX9726
ACKNOWLEDGE
B5
48
B7
0
1
B1 B0
64
CONDITION
A
STOP
B4
DD
P
A write to the MAX9726 includes transmission of a
START condition, the slave address with the R/W bit set
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 MAX9726 only accepts write data, but it acknowl-
edges the receipt of its address byte with the R/W bit
set to 1. The MAX9726 does not write to the SDA bus in
the event that the R/W bit is set to 1. Subsequently, the
master reads all 1’s from the MAX9726. Always set the
R/W bit to zero to avoid this situation.
The MAX9726 has one command register that is used
to enable/disable shutdown, enable/disable BassMax,
and set the volume. Table 2 describes the function of
the bits contained in the command register.
Set B7 to 0 to shutdown the MAX9726. The MAX9726
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 MAX9726 to operate normally (see Table 3).
Set B6 to 1 to enable BassMax (see Table 4). The out-
put signal’s low-frequency response is boosted accord-
ing to the external components connected between
OUT_ and BM_. See the Gain-Setting Components sec-
tion for details on choosing the external components.
Adjust the MAX9726’s volume with control bits [5:0].
The volume is adjustable to one of 64 steps ranging
from full mute to the maximum gain set by the external
components. Table 5 lists all the possible volume set-
tings for the MAX9726. Figure 7 shows the volume-con-
trol transfer function for the MAX9726.
Table 4. BassMax Control
BassMax Disabled
BassMax Enabled
Volume (See Table 5)
B3
MODE
B2
B1
Command Register
Write Data Format
B6
0
1
B0