Integration Guide
Table Of Contents
- Preface
- Contents
- 1 System description
- 1.1 Overview
- 1.2 Architecture
- 1.3 Pin-out
- 1.4 Operating modes
- 1.5 Power management
- 1.6 System functions
- 1.7 RF connection
- 1.8 SIM interface
- 1.9 Serial Communication
- 1.10 Audio
- 1.11 ADC input (LEON-G100 only)
- 1.12 General Purpose Input/Output (GPIO)
- 1.13 M2M Setup Schematic Example
- 1.14 Approvals
- 2 Design-In
- 3 Handling and soldering
- 4 Product Testing
- Appendix
- A Extra Features
- B Glossary
- Related documents
- Revision history
- Contact
LEON-G100/G200 - System Integration Manual
GSM.G1-HW-09002-F3 Preliminary System description
Page 58 of 101
In headset mode the main uplink audio path is “Headset microphone”, the main downlink audio path is “Mono
headset” (refer to u-blox 2G GSM/GPRS AT Commands Manual [2]; AT+USPM command: <main_uplink>,
<main_downlink> parameters).
The audio path used in headset mode:
Headset microphone must be connected to MIC_BIAS2/MIC_GND2
Headset receiver must be connected to HS_P
Figure 37 shows an application circuit connecting a headset (with a 2.2 kΩ electret microphone and a 32 Ω
receiver) to the LEON-G100/G200 modules. Pin 1 & 2 are shorted in the headset connector, causing HS_DET to
be pulled low. When the headset plug is inserted HS_DET is pulled internally by the module, causing a rising
edge for detection.
Perform the following steps on the application board (as shown in Figure 37; the list of components to be
mounted is shown in Table 23):
Mount a series capacitor on the HS_P line to decouple the bias. 10 µF ceramic capacitor (e.g. Murata
GRM188R60J106M) is required if a 32 Ω receiver or a load with greater impedance (as a single ended
analog input of a codec) is connected to the line. 22 µF series capacitor (e.g. Murata GRM21BR60J226M) is
required if a 16 Ω receiver is connected to the line
Mount a 82 nH series inductor (e.g. Murata LQG15HS82NJ02) on each microphone line, and a 27 pF bypass
capacitor (e.g. Murata GRM1555C1H270J) on all audio lines to minimize RF coupling and the TDMA noise
LEON-G100/G200
C4
AUDIO HEADSET
CONNECTOR
C1 C2 C3
J1
2
5
3
4
6
1
L1
L2
18
HS_DET
37
HS_P
42
MIC_GND2
41
MIC_BIAS2
D1
Figure 37: Headset mode application circuit
Reference
Description
Part Number - Manufacturer
C1, C2, C3
27 pF Capacitor Ceramic COG 0402 5% 25 V
GRM1555C1H270JZ01 - Murata
C4
10 µF Capacitor Ceramic X5R 0603 20% 6.3V
GRM188R60J106M - Murata
L1, L2
82nH Multilayer inductor 0402
(self resonance frequency ~1 GHz)
LQG15HS82NJ02 - Murata
J1
Audio Headset 2.5 mm Jack Connector
SJ1-42535TS-SMT - CUI, Inc.
D1
Varistor Array for ESD protection
CA05P4S14THSG - EPCOS
Table 23: Example of components for headset jack connection
1.10.1.5 Hands-free mode
Hands-free mode can be implemented using a loudspeaker and a dedicated microphone.