Earphone Interface Design; Speaker Amplifier Design - Quectel WCDMA UG Series Manual

3.6. Earphone Interface Design

The following figure shows the single-ended application for earphone design.
MICN_PCM
MICP_PCM
SPKP_PCM

3.7. Speaker Amplifier Design

If the 8Ω speaker is applied, it is recommended to add an audio amplifier.
SPKP_PCM
SPKN_PCM
WCDMA_UGxx_Audio_Design_Note
4.7uF
Differential layout
0R
0R 22uF
Figure 8: Earphone Design
Amplifier circuit
Ri
Ri
Figure 9: Speaker Amplifier Design
UMTS/HSPA Module Series
WCDMA UGxx Audio Design Note
Close to Socket
10pF
33pF
10pF 33pF
Close to Speaker
33pF
10pF
33pF
10pF
10pF 33pF
Confidential / Released
Earphone
3
4
2
1
32Ω
8Ω
16 / 56