MAX9723BETE データシートの表示（PDF） - Maxim Integrated

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MAX9723BETE

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

Maxim Integrated 

MAX9723

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 detec-

tion of unsuccessful data transfers. An unsuccessful 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, the mas-

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

ter 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 command 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 section for details

on choosing the external components.

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