Switch S3; J4, J9, And J10 Configuration: Power Options; Voltage Reference - Texas Instruments ADS1256EVM-PDK User Manual

Voltage Reference

4.1.6 J10 Pins 5-6: AGND Select
Shorting this jumper connects the ADS1256EVM ground net to AGND. For normal operation, J4.1-2, J4.3-
4, and J4.9-10 must be connected (either directly or through an ammeter); either J4.5-6 or J4.7-8 must be
connected, and either (or both) of J4.11-12 and J4.13-14 must be connected, as well. Otherwise, the
board will not function. Refer to
Row
1-2
3-4
5-6
7-8
9-10
11-12
13-14
5 Voltage Reference
The ADS1256EVM has several reference options that can be selected by switch S3. First, there are
connections to apply an external reference voltage to the analog input header. The user can apply a
reference voltage to J1.18 and J1.20 in order to set the reference.
The ADS1256 also has a buffered REF5025 on board. This 2.5V reference can also be selected by switch
S3. VRN to VRP can be set from AGND to 2.5V or from 2.5V to AVDD.
appears on the board. A description of switch S3 is provided in
10
ADS1256EVM and ADS1256EVM-PDK
Table 5 for details.
Table 5. J4, J9, and J10 Configuration: Power Options
Name
ADC AVDD
ADC AVSS
1.8V select
3.3V select
ADCDVDD
DGND
AGND
Figure 4. Switch S3
Copyright © 2003–2018, Texas Instruments Incorporated
Function
AVDD supply current measurement point for the
ADC. Must be connected for operation.
AVSS supply current measurement point for the
ADC. Must be connected for operation.
When shorted, DVDD is sourced from the 1.8V
power-supply input pin. Should not be connected at
the same time as 7-8.
When shorted, DVDD is sourced from the 3.3V
power-supply input pin. Should not be connected at
the same time as 5-6.
DVDD supply current measurement point for the
ADC. Must be connected for operation.
Connects DGND to board ground.
Connects AGND to board ground.
Figure 4
Table 6.
SBAU090E – November 2003 – Revised November 2018
www.ti.com
illustrates how switch S3
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