MAX9879 Maxim Integrated Products, MAX9879 Datasheet - Page 15

• Manufacturer Part Number: MAX9879
• Description: Stereo Class D Audio Subsystem
• Manufacturer: Maxim Integrated Products

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The MAX9879 signal path consists of flexible inputs,
signal mixing, volume control, and output amplifiers
(Figures 1a, 1b, 1c).
The inputs can be configured for single-ended or differ-
ential signals (Figure 2). The internal preamplifiers fea-
ture three programmable gain settings of 0dB, +5.5dB,
and +20dB. Following preamplification, the input sig-
nals are mixed, volume adjusted, and routed to the
headphone and speaker amplifiers based on the out-
put mode configuration (see Table 6). The volume con-
trol stages provide up to 75dB attenuation. The
headphone amplifiers provide +3dB of gain while the
speaker amplifier provides +18dB of additional gain.
C2, C3, C4,
BUMP
A5, B5
A1
A2
A3
A4
A6
B1
B2
B3
B4
B6
C1
C5
C6
D1
D2
D3
D4
D5
D6
E1
E2
E3
E4
E5
E6
PGNDR
PGNDL
PVDDR
OUTR+
PVDDL
OUTL+
OUTR-
NAME
OUTL-
RXIN+
SHDN
V
RXIN-
GND
BIAS
INB1
INA1
INB2
INA2
C1N
SDA
HPR
C1P
HPL
SCL
V
V
CCIO
______________________________________________________________________________________
DD
SS
Detailed Description
Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor between C1P and C1N.
Left-Speaker Negative Output
Left-Channel Class D Power Supply. Bypass with a 1µF capacitor to PGNDL.
Left-Speaker Positive Output
Right-Channel Class D Power Ground
Right-Speaker Negative Output
Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor between C1P and C1N.
Receiver Bypass Negative Input
Left-Channel Class D Power Ground
Receiver Bypass Positive Input
Right-Channel Class D Power Supply. Bypass with a 1µF capacitor to PGNDL.
Headphone Amplifier Negative Power Supply. Bypass with a 1µF capacitor to PGND.
Analog Ground
Right-Speaker Positive Output
Headphone Amplifier Right Output
Common-Mode Bias. Bypass to GND with a 1µF capacitor.
Input B1. Left input or negative input.
Input A1. Left input or negative input.
Serial-Clock Input. Connect a pullup resistor from SDA to V
Serial-Data Input/Output. Connect a pullup resistor from SDA to V
Headphone Amplifier Left Output
Analog Supply. Connect to PVDDL and PVDDR. Bypass with a 1µF capacitor to GND.
Input B2. Right input or positive input.
Input A2. Right input or positive input.
Active-Low Shutdown Input Signal
I
with DirectDrive Headphone Amplifier
2
C Power Supply
Stereo Class D Audio Subsystem
Signal Path
When an input is configured as mono differential, it can
be routed to both speakers or to both headphones.
When an input is stereo, it is routed to either the stereo
headphones or the stereo speakers. Simultaneous oper-
ation is also possible. If the right speaker amplifier is dis-
abled then the left and right audio signals are summed
into the left speaker amplifier and vice-versa.
When the application does not require the use of both
INA_ and INB_, the SNR of the MAX9879 is improved
by deselecting the unused input through the I
mode register and AC-coupling the unused inputs to
ground with a 330pF capacitor. The 330pF capacitor
and the input resistance to the MAX9879 form a high-
pass filter preventing audible noise from coupling into
the outputs.
FUNCTION
CCIO
.
CCIO
.
Pin Description
2
C output
15