
TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R07
Advance Information
Design-in
Page 118 of 158
TOBY-L2 series
(except ‘00’, ‘01’, ‘50’ versions)
GPIO6
R2
R1
BCLK
GND
U1
LRCLK
Audio
Codec
SDIN
SDOUT
55
SDA
54
SCL
SDA
SCL
61
MCLK
GND
IRQn
R3
C3
C2
C1
5
V_INT
VDD
1V8
MICBIAS
C4
R4
C5
C6
EMI1
MICLN
MICLP
D1
Microphone
Connector
EMI2
MIC
C12 C11
J1
MICGND
R5
C8
C7
D2
SPK
Speaker
Connector
OUTP
OUTN
J2
C10 C9
C14 C13
EMI3
EMI4
52
I2S_CLK
50
I2S_WA
51
I2S_TXD
53
I2S_RXD
Figure 66: I
2
S interface application circuit with an external audio codec to provide voice capability
Reference
Description
Part Number – Manufacturer
C1
100 nF Capacitor Ceramic X5R 0402 10% 10V
GRM155R71C104KA01 – Murata
C2, C4, C5, C6
1 µF Capacitor Ceramic X5R 0402 10% 6.3 V
GRM155R60J105KE19 – Murata
C3
10 µF Capacitor Ceramic X5R 0603 20% 6.3 V
GRM188R60J106ME47 – Murata
C7, C8, C9, C10
27 pF Capacitor Ceramic COG 0402 5% 25 V
GRM1555C1H270JZ01 – Murata
C11, C12, C13, C14
10 nF Capacitor Ceramic X5R 0402 10% 50V
GRM155R71C103KA88 – Murata
D1, D2
Low Capacitance ESD Protection
USB0002RP or USB0002DP – AVX
EMI1, EMI2, EMI3,
EMI4
Chip Ferrite Bead Noise/EMI Suppression Filter
1800 Ohm at 100 MHz, 2700 Ohm at 1 GHz
BLM15HD182SN1 – Murata
J1
Microphone Connector
Various manufacturers
J2
Speaker Connector
Various manufacturers
MIC
2.2 k
Electret Microphone
Various manufacturers
R1, R2
4.7 k
Ω
Resistor 0402 5% 0.1 W
RC0402JR-074K7L - Yageo Phycomp
R3
10 k
Ω
Resistor 0402 5% 0.1 W
RC0402JR-0710KL - Yageo Phycomp
R4, R5
2.2 k
Ω
Resistor 0402 5% 0.1 W
RC0402JR-072K2L – Yageo Phycomp
SPK
32
Speaker
Various manufacturers
U1
16-Bit Mono Audio Voice Codec
MAX - Maxim
Table 41: Example of components for audio voice codec application circuit
Do not apply voltage to any I
2
S pin before the switch-on of I
2
S supply source (
V_INT
), to avoid latch-up of
circuits and allow a proper boot of the module. If the external signals connected to the cellular module
cannot be tri-stated or set low, insert a multi channel digital switch (e.g. TI SN74CB3Q16244, TS5A3159,
or TS5A63157) between the two-circuit connections and set to high impedance before
V_INT
switch-on.
ESD sensitivity rating of I
2
S interface pins is 1 kV (Human Body Model according to JESD22-A114). Higher
protection level could be required if the lines are externally accessible and it can be achieved by mounting
a general purpose ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to accessible points.
If the I
2
S digital audio pins are not used, they can be left unconnected on the application board.
2.7.1.2
Guidelines for digital audio layout design
I
2
S interface and clock output lines require the same consideration regarding electro-magnetic interference as
any other high speed digital interface. Keep the traces short and avoid coupling with RF lines / parts or sensitive
analog inputs, since the signals can cause the radiation of some harmonics of the digital data frequency.