Analog Input
1-3
EVM Overview
Table 1−1. Analog Interface
Reference
Designator
Description
Factory Set Condition
Reference
Designator
Description
1−2
2−3
Analog Input options
W1
Selects AIN_N source
Installed
Not installed
W5
Selects AIN source
Installed
Not installed
Reference voltage options
W3
Selects VREFN source
Installed
Not installed
W4
Selects VCOM source
Installed
Not installed
W2
Selects VREFP source
Installed
Not installed
W6
Connects VCM for on board reference
Installed
Modulator clock
W7
Modulator clock source
Installed
Not installed
1.4
Analog Input
There are various options available to deliver the signal to the ADC:
-
Single-ended via SMA connector at J6.
-
Single-ended via socket strip/header at J1/P1 connector.
-
Differentially via socket strip/header at J1/P1 connector.
The default configuration used by the EVM is shown in Figure 1−2. It provides
a convenient method to convert a single-ended bipolar signal into a differential
signal. The signal is centered on a common mode voltage derived from the
reference section of the EVM.
Figure 1−2. Default Configuration Used by the EVM
Gain = 1
Gain = −1
Common Mode Voltage
Common Mode Voltage
To W1 and W5
The differential signal is routed via W1 and W5, which enables the user to
provide an external
signal.
1.5
External Reference
The selection between the device’s internal reference and an external
reference is made by SW1. 8−9
