MAX9875 Datasheet, PDF (20/30 Pages) Maxim Integrated Products – Low RF Susceptibility, Mono Audio Subsystem with DirectDrive Headphone Amplifier

Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
The MAX9875 is controlled through five I²C program-
mable registers. Table 1 shows the MAX9875’s com-
plete register map. Tables 2, 3, and 5 show the
individual registers.
Table 1. Register Map
I²C Interface
I²C Address
The slave address of the MAX9875 is 1001101R/(W).
REGISTER
REGISTER
ADDRESS
POR STATE
B7
B6
B5
B4
B3
B2
B1
B0
Input Mode
Control
0x00
0x40
0
ZCD ΔINA ΔINB
PGAINA
PGAINB
Speaker
Volume
Control
0x01
0x00
0
0
0
SVOL (Table 4)
Left
Headphone
Volume
Control
0x02
0x00
0
0
0
HPLVOL (Table 4)
Right
Headphone
Volume
Control
0x03
0x00
Output Mode
Control
0x04
0x49
Table 2. Input Mode Control
0
0
0
SHDN
0
OSC (Table 6)
HPRVOL (Table 4)
OUTMODE (Table 7)
REGISTER
B7
0x00
0
B6
ZCD
B5
ΔINA
B4
ΔINB
B3
B2
PGAINA
B1
B0
PGAINB
I²C Register Description
Zero-Crossing Detection (ZCD)
Zero-crossing detection limits distortion in the output
signal during volume transitions by delaying the transi-
tion until the mixer output crosses the internal bias volt-
age. A timeout period (typically 60ms) forces the
volume transition if the mixer output signal does not
cross the bias voltage.
1 = Zero-crossing detection is enabled.
0 = Zero-crossing detection is disabled.
Differential Input Configuration (ΔIN_)
The inputs INA_ and INB_ can be configured for mono
differential or stereo single-ended operation.
1 = IN_ is configured as a mono differential input with
IN_2 as the positive and IN_1 as the negative input.
0 = IN_ is configured as a stereo single-ended input
with IN_2 as the right and IN_1 as the left input.
Preamplifier Gain (PGAIN_)
The preamplifier gain of INA_ and INB_ can be pro-
grammed by writing to PGAIN_.
00 = 0dB
01 = +9dB
10 = +20dB
11 = Reserved
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