Integration Manual

TSD-19090601 - R15 Contents Page 114 of 143
R2,R3
2.2 k Resistor 0402 0.1% 62.5 mW
RN73R1ETP2201B25 - KOA
D1,D2
Low Capacitance ESD Protection
USB0002RP or USB0002DP – AVX
U1
LDO Linear Regulator 1.8 V 0.3 A
LT1962EMS8-1.8 - Linear Technology
U2
Audio Voice Codec
ALC5660 - Realtek
Table 45: Example of components for an ACL5660 audio voice codec application circuit
☞ Do not apply voltage to any PCM digital audio interface pins before the switch-on of the supply source
(V_INT), to avoid latch-up of circuits and allow a clean boot of the module.
☞ The ESD sensitivity rating of the I
2
S interface pins is 1 kV (Human Body Model according to JESD22-
A114). A 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 the accessible points.
☞ If the PCM digital audio pins or the I2C pins (I2C_SDA1, I2C_SCL1) are not used, they can be left
unconnected on the application board.
2.8.2 Guidelines for digital audio layout design
I
2
S interface and clock output lines require the same considerations regarding electromagnetic 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.
2.9 ADC interfaces
☞ The ADC pins are not supported by the "0x" product feature versions.
2.9.1 Guidelines for ADC circuit design
TOBY-L3 series modules include Analog to Digital Converter inputs (ADC1, ADC2), which can be handled
by means of the dedicated open CPU API.
The ADC pins can be connected to external circuits for general purpose voltage measurements.
The voltage value at the ADC input must be within the range reported in the TOBY-L3 series Data Sheet [1].
If an external voltage divider is implemented to increase the measurement voltage range, check the input
resistance of the ADC inputs reported in the TOBY-L3 series Data Sheet [1]: if the equivalent of the external
circuit has a significant value as compared to the input resistance of the ADC inputs, this should be taken
into account and corrected to properly associate the ADC response to the voltage source value,
implementing an appropriate ADC calibration procedure.