Sierra Wireless AirPrime SL808 Series, Product Technical Specification & Customer Design Manuallines, Page: 57 / 122

Rev 1 Dec.10 Proprietary and Confidential - Specifications subject to change 57
Table 4-24 lists the recommended components to use in creating the LC filter.
4.10.3 Speaker features
The speaker can be connected in either differential or single-ended mode:
• Differential mode—Default method (recommended). Rejects common mode
noise and TDMA noise.
• Single-ended mode—Requires good ground plane, filtering, and shielding to
avoid audio path disturbances. Experiences power loss (power is divided by 4
in a single-ended connection) compared to differential connection.
The gain of each speaker output channel is internally adjusted and can be tuned
using AT commands. For more information on AT commands, see [3] AirPrime
MC8xxx Embedded Modules Extended AT Command Reference.
Discreet components (for example, resistors and capacitors) are not needed for
this interface.
Table 4-25 lists the typical values of both speaker outputs.
4.10.3.1 Speakers output power
Because SPK can provide more power, it can be connected in differential mode.
The maximal specifications given below are available with the maximum power
output configuration values set by AT command, and the typical values are
recommended.
Caution: It is mandatory not to exceed the maximal speaker output power and the
speaker load must be in accordance with the gain selection (gain is controlled by AT
command). Exceeding beyond the specified maximal output power may damage the
AirPrime SL808X Embedded Module.
Table 4-24: Recommended components for a MIC single-ended
connection
Component Value Notes
C1
12–33 pF Must be tuned depending on
the design.
C2
Must be tuned depending on
the design.
L1
Must be tuned depending on
the design.
Table 4-25: Speaker information
Parameter Typical Unit Connection
Z (SPK_P, SPK_N)
4

Single-ended mode
Z (SPK_P, SPK_N)
8

Differential mode