Specifications

WM_PRJ_Q2501_PTS_002 - 001
March 2004
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Page: 42 / 79
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3.3.6.3.3 Single-ended connection
Typical implementation
:
SPKxP
C1
+
SPKxN
C2
+
Zhp
Speaker
C3
33 pF
to
100 pF
R1
Figure 24: Speaker single-ended connection
4.7 µF < C1 < 47 µF (depending on speaker characteristics and output power).
C1 = C2.
R1 = Zhp.
Using a single-ended connection includes losing of the output power (- 6 dB)
compared to a differential connection.
Nevertheless in a 32-Ohm speaker case, you should use a cheaper and smaller
solution: R1 = 82 Ohms and C2 = 4.7 µF (ceramic).
The connection between the module pins and the speaker must be designed to
keep the serial impedance lower than 1.5 Ω in differential mode.
3.3.6.3.4 Recommended characteristics for the speaker
 Type: 10 mW, electro-magnetic.
 Impedance:
 Z = 8 Ω for handset,
 Z = 32 Ω for headset or hands-free kit.
 Sensitivity: 110 dB SPL min. (0 dB = 20 µPa).
 Frequency response compatible with the GSM specifications.