MAX9856ATL/V+ Maxim Integrated, MAX9856ATL/V+ Datasheet - Page 31

• 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 various analog inputs. All inputs
have independent gain control for maximum flexibility.
AUXIN is a mono auxiliary input that can be used for
mixing alarms, beeps, and sound effects into the head-
phone outputs or ADC input. The AUXIN signal has a
dedicated PGA for gain adjustment and can be mixed
into the headphone output signal directly, bypassing
the output mixer and volume control. AUXIN can also
serve as an input for making precise measurements in
the system. In this mode, the PGA is bypassed,
increasing the impedance of the input, and is directly
connected to the ADC.
Three microphone inputs are available. Two are pseudo-
differential inputs with a shared ground connected to the
Figure 3. Typical Microphone Connections: (a) Pseudo-Differential, (b) Differential
Table 12. Audio Input Control Registers
REG
0x11
0x12
0x13
0x14
0x15
0x16
0x17
2.2kΩ
______________________________________________________________________________________
B7
0
0
0
0
0
0
(a)
MICBIAS
JACKSNS
DirectDrive Headphone Amplifiers
B6
0
0
0
0
Analog Inputs
PAENR
PAENL
Low-Power Audio CODEC with
MICL/MICR
MICGND
B5
0
0
0
0
B4
0
inverting input of the microphone preamplifier. The third
is a fully differential input. Stereo microphones that share
a common return path can take advantage of the
pseudo-differential configuration by connecting the com-
mon return to the MICGND, canceling common-mode
noise. Figure 3 shows the typical application circuit for
both single-ended and differential microphones. The
microphone preamplifier and PGA provide a wide range
of gain options. The microphone inputs can also be used
as additional line inputs when the gain is set to 0dB.
A single low-noise bias voltage output is available
(MICBIAS) to bias microphones from a clean supply
with an external bias resistor. There are two selectable
microphone bias voltages that can be selected
depending on the power-supply voltage. Table 12 lists
the audio input control registers and bit description.
PGADS
MMIC
B3
2.2kΩ
2.2kΩ
PGAAUX
PGAMR
PGAML
MBSEL
PGAL1
PGAL2
B2
(b)
MICBIAS
JACKSNS
B1
0
INLP
INLN
LMICDIF
B0
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