Figure 16: Speaker Outputs (Differential Mode); Figure 17: Speaker Outputs (Single-Ended Connection) - Wavecom WISMO Quik Q2406 Customer Design Manuallines

2.3.2.2 Speaker outputs
2.3.2.2.1 Common speaker output characteristics
The connection can be differential or single-ended
connection to reject common mode noise and TDMA noise is strongly
recommended. Moreover in single-ended mode, ½ of the power is
When using a single-ended connection, be sure to have a very good ground
plane, a very good filtering as well as shielding in order to avoid any disturbance
on the audio path.
Speaker outputs SPK2 are push-pull amplifiers and can be loaded down to 150 Ω
.
and up to 1 nF These outputs are differential and the output power can be
adjusted by step of 2 dB. The output can be directly connected to a speaker.
Differential Connection:
Impedance of the speaker amplifier output in differential mode : R ≤ 1Ω +/-10 %

Figure 16: Speaker outputs (differential mode)

Single-ended Connection:
Typical implementation:
Speaker

Figure 17: Speaker outputs (single-ended connection)

C1 = from 4.7 µF to 47 µF as per the speaker characteristics and the output
power.
C1=C2; R1= Speaker Impedance.
Nevertheless in a 32 Ω speaker case, you should use a cheaper and smaller
solution : R1 = 82 Ω et C2 = 4.7 µF (ceramic).
Confidential©
This document is the sole and exclusive property of WAVECOM. Not to be
distributed or divulged without prior written agreement.
33 to
100 pF
C3
ZHP
All rights reserved
WM_PRJ_Q2400_PTS_005 -007
but using a differential
SPKxP
C1
+
C2 R1
+
18th January 2006
lost.
SPKxN
SPKxP
SPKxN
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