Texas Instruments PCM1840EVM, User Manual, Page: 5 / 21

MK1
IN1P IN1M IN2P IN2M IN3P IN3M IN4P IN4M
PCM1840
IN1P IN1M IN2P IN2M IN3P IN3M IN4P IN4M
J16
J15
MICBIAS
J14
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Hardware Configuration
5 SBAU345 – March 2020
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PCM1840 Evaluation Module
3.1 PCM1840EVM Inputs
The PCM1840 device is intended to be driven with differential line inputs or microphone inputs. Each of
the inputs has a 1-µF AC coupling film capacitor. Coupled with the 2.5-k
Ω
input impedance, this sets the
high pass filter cutoff frequency at approximately 63 Hz. This can be adjusted by replacing the input AC
coupling capacitors on the EVM if necessary.
Figure 1 shows the architecture of the inputs to the
evaluation module. The EVM supports a differential full scale input range of 2 V
RMS
with an AVDD of 3.3 V.
Figure 1. PCM1840EVM Input Architecture
3.1.1 Line Inputs
For the line input configuration, shown in Figure 2 , the PCM1840 captures the audio signal provided
through terminals J1 (IN1), J2 (IN2), J3 (IN3), and J4 (IN4). The input accepted in this mode is a
differential, 2 V
RMS
, full-scale audio signal. Single-ended inputs are not supported by the PCM1840 device
and the inputs should be AC coupled.
Figure 2. PCM1840EVM Connection for Line Input Application