Sierra Wireless AirPrime SL808 Series, Технические характеристики продукта и руководство по дизайну для клиентов, Страница: 59 / 122

Rev 1 Dec.10 Proprietary and Confidential - Specifications subject to change 59
If a single-ended connection is used, only one of either SPK outputs have to be
chosen. The result is a maximal output power divided by 4.
4.10.3.3 Differential connection example
Figure 4-9: Example - SPK differential connection
The impedance of the speaker amplifier output in differential mode is
R

1
 
10%.
Note that the connection between the speaker and the AirPrime SL808X
Embedded Module pins must be designed to keep the serial impedance lower
than 3

when it is connected in differential mode.
4.10.3.4 Single-ended connection example
Figure 4-10: Example - SPK single-ended connection
Take note of the following when connecting the speaker in single-ended mode:
• 6.8µF < C1 < 47 µF (depending on the characteristics of the speaker and the
output power)
• C1 = C2
• R1 = Zhp
Table 4-27: Speaker interface parameters
Parameter / Description Test
Min
a
Typ
a
Max
a Units
Output DC offset voltage between
MIC1_P and MIC1_N, SPK_P and
SPK_N
Fully differential -20 20 mV
Output common mode voltage,
SPK_P and SPK_N
Measured at each
output pin with respect
to AVSS:
V
DD
= 2.5 V to 2.7 V
1.13 1.25 1.38 V
Z
OUT1
Differential output impedance At 1.02 kHz, for outputs
SPK_P and SPK_N
1

a. Preliminary values
SPK_P
SPK_N
SPK_P
SPK_N
R1
+
+
C2
C1
C3
33 pF
to
100 pF
Zhp