User's Manual
Table Of Contents
- Contents
- Table Index
- Figure Index
- 0. Revision history
- 1. Introduction
- 2. Product concept
- 3. Application interface
- 3.1. Pin
- 3.2. Operating modes
- 3.3. Power supply
- 3.4. Power on and down scenarios
- 3.5. Charging interface
- 3.6. Power saving
- 3.7. Summary of state transitions
- 3.8. RTC backup
- 3.9. Serial interfaces
- 3.10. Audio interfaces
- 3.11. SIM card interface
- 3.12. SD card interface
- 3.13. PCM interface
- 3.14. ADC
- 3.15. Behaviors of the RI
- 3.16. Network status indication
- 3.17. Operating status indication
- 4. Antenna interface
- 5. Electrical, reliability and radio characteristics
- 6. Mechanical dimensions
- 7. Storage and manufacturing
- Appendix A: GPRS coding schemes
- Appendix B: GPRS multi-slot classes
M80 Hardware Design
M80_HD_V1.2 - 54 -
3.10.2. Microphone interfaces design
AIN1 and AIN2 channels come with internal bias supply for external electret microphone. A
reference circuit is shown in the following figure.
10pF
33pF
33pF
33pF
Close to Microphone
MICxP
MICxN
GND
GND
Differential layout
Module
Electret
Microphone
GND
GND
10pF
10pF
GND
GND
ESD
ANTI
ESD
ANTI
Figure 27: Reference design for AIN1&AIN2
3.10.3. Receiver and speaker interface design
SPK1P
SPK1N
Differential layout
10pF
10pF
33pF
33pF
33pF
Close to receiver
GND
GND
10pF
ESD
ANTI
ESD
ANTI
Module
Figure 28: Reference design for AOUT1