MAX9856ATL/V+ Maxim Integrated, MAX9856ATL/V+ Datasheet - Page 35

• Manufacturer Part Number: MAX9856ATL/V+
• Description: Interface - CODECs Low-Power Audio Codec With Directdrive. Headphone Amplifiers
• Manufacturer: Maxim Integrated
• Series: MAX9856r

Specifications of MAX9856ATL/V+

• Resolution: 18 bit
• Interface Type: Serial (I2C)
• Number Of Adcs: 2
• Number Of Dacs: 2
• Operating Supply Voltage: 1.71 V to 3.6 V
• Supply Current: 2.9 mA
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 1.71 V
• Thd Plus Noise: 82 dB

The MAX9856 features stereo headphone amplifiers and
line output amplifiers with DirectDrive technology.
DirectDrive eliminates the need for bulky and expensive
DC-blocking capacitors on the outputs. The DirectDrive
biasing scheme is illustrated in Figure 4. The head-
phone outputs have separate left/right volume controls
while the line outputs produce a fixed level signal.
The audio outputs feature ground sensing, which is
intended to reduce the effect of ground noise. In many
systems, the ground return for line outputs and head-
phone jacks is used by other functions such as video
Figure 4. Traditional Amplifier Output vs. MAX9856 DirectDrive Output
Figure 5. Ground Sense Connection
CONVENTIONAL AMPLIFIER BIASING SCHEME
______________________________________________________________________________________
DirectDrive Headphone Amplifiers
Audio Outputs
Low-Power Audio CODEC with
GND
AVDD
AVDD/2
GND
HPR
signals and microphone signals. The sharing of ground
can result in interference that is audible. The MAX9856’s
ground sense provides a path for the interfering signal to
be input and combined with the output audio signal to
reduce the audibility of the interference. Connect HGND-
SNS directly to the ground terminal of the headphone jack
to enable ground sense on the headphones (Figure 5).
Similarly connect LGNDSNS directly to the ground termi-
nal of a line output jack to enable ground sense on the
line outputs. If ground sense is not required, connect
HGNDSNS and LGNDSNS to AGND. Table 13 lists the
audio output control registers and bit description.
HPL
DirectDrive AMPLIFIER BIASING SCHEME
HPR
HGNDSNS
HPL
AVDD
SVSS
AGND
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