Ublox SARA-G450 Series - Page 110

SARA-G450 - System integration manual
UBX-18046432 - R08 Design-in Page 110 of 143
C1-Public
 Provide additional ESD protection (e.g. Bourns CG0402MLE-18G varistor) if the analog audio lines
will be externally accessible on the application device, according to EMC/ESD requirements of the
custom application. The protection should be mounted close to accessible point of the line (D1-D4
parts in the circuit described in Figure 70).
SARA-G450
49
MIC_P
R1
R2 R4
44
SPK_P
48
MIC_N
45
SPK_N
R3
C1
46
MIC_BIAS
47
MIC_GND
C2
C3
C6 C7
L2
L1
C5C4
LSPKLoudspeaker
connector
J2
Microphone
connector
MIC
J1
OUT+
IN+
GND
U1
OUT-
IN-
C8
C9
R5
R6
VDD
C11C10
Audio
amplifier
VCC
D3
D1
D4
D2
Figure 70: Analog audio interface application circuit
Reference
Description
Part number – Manufacturer
C1, C10
10 µF capacitor ceramic X5R 0603 20% 6.3 V
GRM188R60J106ME47 – Murata
C2, C3, C11
100 nF capacitor ceramic X7R 0402 10% 16 V
GRM155R71C104KA88 – Murata
C4, C5, C6, C7
27 pF capacitor ceramic C0G 0402 5% 25 V
GRM1555C1H270JA01 – Murata
C8, C9
47 nF capacitor ceramic X7R 0402 10% 16V
GRM155R71C473KA01 – Murata
D1, D2, D3, D4
Low capacitance ESD protection
CG0402MLE-18G - Bourns
J1
Microphone connector
Generic manufacturer
J2
Loudspeaker connector
Generic manufacturer
L1, L2
82 nH multilayer inductor 0402
(self-resonance frequency ~1 GHz)
LQG15HS82NJ02 – Murata
LSPK
8  loudspeaker
Generic manufacturer
MIC
2.2 kΩ electret microphone
Generic manufacturer
R1, R2, R3, R4
2.2 kΩ resistor 0402 5% 0.1 W
RC0402JR-072K2L – Yageo Phycomp
R5, R6
0 Ω resistor 0402 5% 0.1 W
RC0402JR-070RL – Yageo Phycomp
U1
Filter-less mono 2.8 W class-D audio amplifier
SSM2305CPZ – Analog Devices
Table 44: Examples of components for analog audio interface application circuit
☞ If the analog audio interface is not used, the analog audio pins (MIC_BIAS, MIC_GND, MIC_P,
MIC_N, SPK_P, SPK_N) can be left unconnected on the application board.