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. Power saving
- 3.6. Summary of state transitions
- 3.7. RTC backup
- 3.8. Serial interfaces
- 3.9. Audio interfaces
- 3.10. SIM card interface
- 3.12. Behaviors of the RI
- 3.13. Network status indication
- 3.14. 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
M95 Hardware Design
M95_HD_V1.0 - 50 -
3.9.2. Microphone interfaces design
AIN1/IN2 channels come with internal bias supply for external electret microphone. A reference
circuit is shown in Figure 26.
MICxP
Differential
layout
Module
10pF
33pF
33pF
33pF
GND
GND
Electret
Microphone
GND
GND
10pF
10pF
GND
GND
ESD
ANTI
ESD
ANTI
33pF
10pF
Close to Module
MICxN
GND
GND
GND
GND
10pF
33pF
33pF
10pF
Close to MIC
Figure 26: Microphone interface design of AIN1&AIN2
3.9.3. Receiver interface design
SPK1P
SPK1N
Differential layout
10pF
10pF
33pF
33pF
33pF
GND
GND
10pF
ESD
ANTI
ESD
ANTI
Module
Close to Receiver
GND
GND
GND GND
Figure 27: Receiver interface design of AOUT1