AD1984B Datasheet, PDF (11/20 Pages) Analog Devices – High Definition Audio SoundMAX Codec

AD1984B
Table 4. Pin Function Descriptions (Continued)
Mnemonic
Pin No.
I/O
Description
FILTER/MIC_BIAS
V_REF _FILT
27
MIC_BIAS-B
28
MIC_BIAS-C
29
MIC_BIAS_IN
33
5.0 V or 3.3 V
O
Voltage Reference Filter.
O
Switchable Microphone Bias. For use with Port B (Pins 21, 22).
O
Switchable Microphone Bias. For use with Port C (Pins 23, 24).
Both MIC bias pins are capable of High-Z, 0 V, 1.65 V, 3.7 V, and 3.9 V (with 5.0 V on
Pin 33), High-Z, 0 V, 1.65 V, 2.86 V, and 3.0 V (with 3.3 V on Pin 33).
I
Source Power for Microphone Bias Boost Circuitry.
Connect this pin to 5.0 V via a low-pass filter. When connected this way the AD1984B
is capable of providing 3.9 V as a mic bias to all of the mic bias pins (except on Pin 31).
POWER AND GROUND
DV_CORE 1.7 V to 1.9 V or 1
FILTER
DV_IO 3.3 V
3
DV_SS
7
DV_DD 1.7 V to 1.9 V or 3.3 V 9
AV_DD 3.3 V
AV_SS
25, 38
26, 42
If 5 V is not available, connect this pin to 3.3 V (AV_DD) via a low-pass filter.
I/O
CAUTION: DO NOT APPLY 3.3 V TO THIS PIN! Filter connection for internal core
voltage regulator.
If Pin 9 is connected to 3.3 V DV_DD, this pin must be connected to filter caps: 10 μF,
1.0 μF and 0.1μF connected in parallel between Pin 1 and DV_SS (Pin 7). Direct, filtered
1.7 V to 1.9 V DV_DD may be applied to Pin 1 to lower the digital power requirements.
Pin 9 MUST be connected to pin 1 in this case.
I
Link Digital I/O Voltage Reference. 3.3 V ± 10%
I
Digital Supply Return (Ground).
I
Digital Supply Voltage 3.3 V ± 10%. This is regulated down to DV_CORE on Pin 1 to
supply the internal digital core internal to the AD1984B. Direct, filtered 1.7 V to 1.9 V
DV_DD may be applied to Pin 1 to lower the digital power requirements. Pin 9 MUST be
connected to Pin 1 in this case.
I
CAUTION: DO NOT APPLY 5 V TO THESE PINS! Analog Supply Voltage 3.3 V ONLY.
Note: AV_DD supplies should be well regulated and filtered as supply noise degrades
audio performance.
I
Analog Supply Return (Ground). AV_SS should be connected to DV_SS using a
conductive trace under, or close to, the AD1984B.
The symbols used in this table are defined as: I = input, O = output, LI = line level input, LO = line level output, HP = output capable of driving
headphone load, MIC = input supports microphones with MIC bias and boost amplifier.
Rev. 0 | Page 11 of 20 | February 2008