MAX9723(2005) 查看數據表（PDF） - Maxim Integrated

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MAX9723
(Rev.:2005)

Stereo DirectDrive Headphone Amplifier with BassMax, Volume Control, and I2C

Maxim Integrated 

Stereo DirectDrive Headphone Amplifier with

BassMax, Volume Control, and I2C

S

SCL

SDA

Sr

P

START

CONDITION

CLOCK PULSE FOR

ACKNOWLEDGMENT

SCL

1

2

8

9

NOT ACKNOWLEDGE

SDA

ACKNOWLEDGE

Figure 4. START, STOP, and REPEATED START Conditions

Figure 5. Acknowledge

Table 1. MAX9723 Address Map

PART

A6

MAX9723A 1

MAX9723B 1

MAX9723C 1

MAX9723D 1

MAX9723 SLAVE ADDRESS

A5 A4 A3 A2 A1 A0 R/W

0011000

0011010

0011000

0011010

Table 2. MAX9723 Command Register

B7

B6

B5

B4 B3 B2 B1 B0

SHUTDOWN

BassMax

ENABLE

MAXIMUM

GAIN

VOLUME

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.

Write Data Format

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,

Table 3. Shutdown Control, SHDN = 1

MODE

B7

MAX9723 Disabled

0

MAX9723 Enabled

1

Table 4. BassMax Control

MODE

B6

BassMax Disabled

0

BassMax Enabled

1

the master reads all 1’s from the MAX9723. Always

reset the R/W bit to 0 to avoid this situation.

Command Register

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.

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