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Component
C1
C2, C3, C4
L1, L2
Single-Ended Connection
When single‐ended connection is used for MIC, MICN is just left open.
Note:
Z2 is from 200Hz to 4kHz. For more details, refer to Table 18 Electrical Characteristics of MIC.
When using a single‐ended connection, bear in mind that:
•
The internal input impedance value becomes 1100Ω, due to the connection of the other end
to ground.
•
The single ended design is very sensitive to TDMA noise.
•
A very good grounding on the MIC is a must in order to ensure good audio performance
against TDMA. Also, special care on the PCB layout must be taken.
•
It is recommended to add L1 and C2 footprints as an LC filter to try to eliminate TDMA
noise.
•
When not used, the filter can be removed by replacing L1 with a 0Ω resistor and by
disconnecting C2, as shown in the following schematic.
WA_DEV_W228_PTS_002
Description/Details
12pF to 33pF
47pF
100nH
Figure 21. Example of a Single-Ended MIC Connection with an LC filter
Rev 001
Product Technical Specification &
Customer Design Guidelines
Notes
needs to be tuned depending on the design
needs to be tuned depending on the design
needs to be tuned depending on the design
Page 59 of 108
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