AD1884
Table 3. AD1884 Pin Descriptions (Continued)
Mnemonic
Pin No.
I/O
Description
AVDD 3.3 V
25, 38
I
CAUTION: DO NOT APPLY 5 V TO THESE PINS!
Analog Supply Voltage 3.3 V ONLY.
MIC_BIAS_IN
Note: AVDD supplies should be well regulated and filtered as supply noise degrades
audio performance.
33
I
Source Power for Microphone Bias Boost Circuitry.
5.0 V or 3.3 V
Connect this pin to 5.0 V via a low-pass filter. When connected this way the AD1884 is
capable of providing +3.9 V as a mic bias to all of the mic bias pins (except on
Pin 31).
If 5 V is not available, connect this pin to +3.3 V (AVDD) via a low-pass filter.
The AD1884 produces a mic bias voltage relative to the AVDD supply
(typically 3.0 V @ AVDD = 3.3 V).
AVSS
26, 42
I
Analog Supply Return (Ground). AVSS should be connected to DVSS using a
conductive trace under, or close to, the AD1884.
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 16 | January 2007