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GE863-QUAD
GE863-PY
1vv0300715 Rev. 1 - 19/09/06
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved page 3 of 79
7.4 Microphone Biasing ................................................................................................................36
7.4.1 Balanced Microphone Biasing ....................................................................................................... 36
7.4.2 Unbalanced Microphone Biasing...................................................................................................37
7.5 Microphone Buffering .............................................................................................................39
7.5.1 Buffered Balanced Mic................................................................................................................... 39
7.5.2 Buffered Unbalanced (Single Ended) Microphone . ...................................................................... 41
8 OUTPUT LINES (Speaker)..............................................................................................44
8.1 Short description.....................................................................................................................44
8.2 Output Lines Characteristics ..................................................................................................45
8.3 General Design Rules ............................................................................................................46
8.3.1 Noise Filtering................................................................................................................................ 46
8.4 Handset Earphone Design .....................................................................................................47
8.5 Hands-Free Earphone (Low Power) Design...........................................................................48
8.6 Car Kit Speakerphone Design ................................................................................................49
8.7 The Evaluation Kit for Telit Modules EVK2.............................................................................50
8.7.1 Short Description ........................................................................................................................... 50
8.7.2 EVK2 Audio Lines Characteristics................................................................................................. 51
9 SIM DESIGN GUIDES .....................................................................................................52
9.1 Data Integrity ..........................................................................................................................52
9.2 EMI/EMC ................................................................................................................................52
9.3 ESD ........................................................................................................................................52
9.4 SIM Supply .............................................................................................................................53
9.5 SCHEMATIC ..........................................................................................................................53
9.6 LAYOUT .................................................................................................................................54
10 General Purpose I/O.......................................................................................................55
10.1 Using a GPIO Pad as INPUT..............................................................................................55
10.2 Using a GPIO Pad as OUTPUT..........................................................................................55
10.3 Using the Alarm Output GPIO6...........................................................................................56
10.4 Using the Buzzer Output GPIO7.........................................................................................56
11 DAC and ADC section....................................................................................................57
11.1 DAC Converter....................................................................................................................57
11.1.1 Description..................................................................................................................................... 57
11.1.2 Enabling DAC ................................................................................................................................ 58
11.1.3 Low Pass Filter Example ............................................................................................................... 58
11.2 ADC Converter....................................................................................................................59
11.2.1 Description..................................................................................................................................... 59
11.2.2 Using ADC Converter .................................................................................................................... 59