![Ublox LISA-U1 Series Скачать руководство пользователя страница 69](http://html1.mh-extra.com/html/ublox/lisa-u1-series/lisa-u1-series_system-integration-manual_3168222069.webp)
LISA-U1 series - System Integration Manual
3G.G2-HW-10002-3
Preliminary
System description
Page 69 of 125
All corresponding differential audio lines must be routed in pairs, be embedded in GND (have the
ground lines as close as possible to the audio lines), and maintain distance from noisy lines such as
VCC
and from components such as switching regulators.
If the audio pins are not used, they can be left unconnected on the application board.
1.11.1.3
Headset mode
Headset mode is the default audio operating mode of the LISA-U120 and LISA-U130 modules. The headset
profile is configured when the uplink audio path is set to “Headset microphone” and the downlink audio path is
set to “Mono headset” (refer to
u-blox AT Commands Manual
[2]: AT+USPM command: <main_uplink>,
<main_downlink> parameters):
Headset microphone must be connected to the module differential input
MIC_P / MIC_N
Headset receiver must be connected to the module differential output
SPK_P / SPK_N
Figure 38 shows an example of an application circuit connecting a headset (with a 2.2 k electret microphone
and a 32 receiver) to the LISA-U120 and LISA-U130 modules, with an external low noise LDO voltage
regulator to provide a proper supply for the microphone.
Mount an 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 TDMA
noise.
The physical width of the audio outputs lines on the application board must be wide enough to
minimize series resistance.
LISA-U120/U130
C2
C3
C4
J1
2
5
3
4
6
1
L2
54
SPK_N
53
SPK_P
39
MIC_N
40
MIC_P
D1
AUDIO HEADSET
CONNECTOR
D2
IN
OUT
GND
Low Noise
LDO Regulator
VMAIN
U1
R4
R1
C6
R3
R2
C5
2V5
Sense lines connected to GND in one star point
L1
C1
C7
Figure 38: Headset mode application circuit
Reference
Description
Part Number - Manufacturer
C1, C2, C3, C4
27 pF Capacitor Ceramic COG 0402 5% 25 V
GRM1555C1H270JA01 - Murata
C5, C6, C7
10 µF Capacitor Ceramic X5R 0603 20% 6.3 V
GRM188R60J106ME47 - Murata
D1, D2
Low Capacitance ESD Protection
USB0002RP or USB0002DP - AVX
L1, L2
82 nH Multilayer inductor 0402
(self resonance frequency ~1 GHz)
LQG15HS82NJ02 - Murata
J1
Audio Headset 2.5 mm Jack Connector
SJ1-42535TS-SMT – CUI, Inc.