WA_DEV_W218_PTS_002 Rev 005 Page 50 of 109
Product Technical Specification &
Customer Design Guidelines
Param eters
Min
Typ
Max
Unit
200 Hz<F<4 kHz
Z2 MICN
(MICP=Open)
Z2 MICP
(MICN=GND)
2.2
Z2 MICN
(MICP=GND)
Impedance between
MICP and MICN
without 2.2K to
GND
4.5
Impedance between
MICP and MICN with
2.2K to GND
3.2
Maximum working voltage
( MICP-MICN)
(THD 10%)
AT+VGT*=1
-
-
210
mVpp
Maximum rating voltage
(MICP or MICN)
-0.5
-
4.4
V
* The input voltage depends on the input micr o gain set by the AT command. Please refer to the document [ 2],
WISMO218 AT Commands Manual.
** Because both MICP and MICN are internally biased, it is necessary to use a coupling capacitor to connect an
audio signal provided by an active generator. Only a passive micr ophone can be directly connected to the MICP input.
Speaker Features The speaker, SPK, can either have a single-ended or a differen tial connection. However, it is strongly
recommended to use a differential connection in order to reject common mode noise and TDMA
noise. Moreover, in single-ended mode, half (½) of the power is lost.
When using a single-ended connection, be sure to have a very good ground plane, very good filtering
as well as shielding in order to avoid any disturbance on the audio path.
Table 17. Speaker Details
Param eter
Typ
Unit
Conne ction
Z (SPKP, SPKN)
16 or 32
Differential mode
Z (SPKP, SPKN)
8
Single-ended mode