Sierra Wireless AIRPRIME WISMO218 - Manual (Page 48)

WA_DEV_W218_PTS_002 Rev 006 April 29, 2010 48
Product Technical Specification &
Customer Design Guidelines Interfaces
Parameters Min Typ Max Unit
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 micro gain set by the AT command. Please refer to document [2],
AirPrime 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 microphone can be directly connected to the MICP input.
3.10.2. Speaker Features
The speaker, SPK, can either have a single-ended or a differential 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 (1/2) 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
Parameter Typ Unit Connection
Z (SPKP, SPKN) 16 or 32  Differential mode
Z (SPKP, SPKN) 8  Single-ended mode
3.10.2.1. Speakers Outputs Power
The maximal specifications given below are available with the maximum power output configuration
values set by an AT command. The typical values are recommended.
3.10.2.1.1. SPK Outputs
The SPK interface allows for both differential and single ended speaker connections.