Texas Instruments PCM1802EVM, User Manual, Page: 5 / 20

5 Interfacing With the EVM
5.1 PCM1802EVM and PCM1803AEVM Inputs
The right and left audio inputs to the PCM1802EVM and PCM1803AEVM can be applied through the RCA
connectors (J7 and J5, respectively) or directly to the test points (TP4 and TP3, respectively). The single-ended
audio inputs pass through an optional antialiasing filter made by R6 and C8 for the right input and R3 and C6 for
the left input. The capacitors can be left depopulated and the resistors replaced with 0-Ω resistors if the filter is
not desired.
An input high-pass filter is created by the 4.7-µF capacitors (C5 and 79) and 20-kΩ input impedance for the
PCM1802 or 40-kΩ input impedance for the PCM1803A. This filter structure results in a high-pass filter cutoff
frequency of approximately 1.69-Hz and 0.84-Hz for the PCM1802EVM and PCM1803AEVM, respectively.
5.2 PCM1802EVM and PCM1803AEVM Output
The digital I/O of the PCM1802EVM and PCM1803AEVM are provided by J8, J9, J15, J16, and J18; the
functions are outlined in
Table 4-1 . The first two pins of each header are duplicated signals to allow for signal
input and monitoring. The third pin of each signal is connected to GND.
6 Switching Between the PCM1802EVM and PCM1803AEVM
As discussed previously, the populated components differ between the two variants, but the PCM1802EVM and
PCM1803AEVM use the same hardware and PCB layout. The variants are differentiated by the label at the top
of the PCB, and by the variant name, DC167-001 (PCM1802EVM) and DC167-002 (PCM1803AEVM), within the
manufacturing files. As such, a PCM1802EVM can be converted to a PCM1803AEVM and vice versa.
The difference between the two variants is located at pin 9 of U1, which can be either the PCM1802 or
PCM1803A. Specifically, all pin functions between the two devices are similar or identical, with the exception of
pin 9. Pin 9 functions as FSYNC for the PCM1802, and functions as TEST for the PCM1803A.
Although the FSYNC and TEST details can be reviewed within each device data sheet, the hardware changes
are captured in
Section 8.1 . Specifically, FSYNC is considered part of the audio serial interface (J16), which can
be used when R9 is populated, and TEST is a test pin that must be grounded for normal operation, which can be
done through R11.
www.ti.com Interfacing With the EVM
SBAU384 – JULY 2021
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PCM1802EVM and PCM1803AEVM Evaluation Module 5
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