Sierra Wireless WISMO218 - Manual (Page 51)

WA_DEV_W218_PTS_002 Rev 005 Page 51 of 109
Product Technical Specification &
Customer Design Guidelines
SPK Outputs
The SPK interface allows for both differential and single ended speaker connections.
SPKP
WISMO218
SPKN
Figure 14. Equivalent Circuit for SPK
Table 18. Electrical Characteristics of SPK
Parameters Min Typ Max Unit
Biasing voltage SPKP and SPKN - 1.4 - V
Output swing
voltage
RL=8 : AT+VGR=6*; single ended - - 1 Vpp
RL=8 : AT+VGR=6*; differential - - 2 Vpp
RL=16  or 32: AT+VGR=6*; single ended - - 1.1 Vpp
RL=16  or 32: AT+VGR=6*; differential - - 2.2 Vpp
RL Load resistance 6 8 - 
IOUT Output current; peak value; RL=8  - - 90 mA
POUT RL=8 ; AT+VGR=10*; - - 65 mW
* The output voltage depends on the output speaker gain set by the AT command. Please refer to document [2]
WISMO218 AT Commands Manual.
If a single-ended connection is used, only SPKP has to be connected. The result is a maximal output
power divided by 2.
Pin Description
Table 19. Analog Audio Interface Pin Descriptions
Signal
Pin
Number
I/O I/O Type Description
MICP 3 I Analog Microphone positive input
MICN 4 I Analog Microphone negative input
SPKP 1 O Analog Speaker positive output
SPKN 2 O Analog Speaker negative output
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