Datasheet

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EVM Operation

7 EVM Operation

This section provides information on the analog input, digital control, and general operating conditions of

the ADS1256EVM.

7.1 Analog Input

The analog input sources can be applied directly to J1 (top or bottom side). Additionally, switches S1 and

S2 must be set to route the input signals from J1. Otherwise, the inputs are used to measure the

reference or inputs shorted to the reference. Switches S1 and S2 are shown in Figure 6.

Figure 6. Switches S1 and S2

7.1.1 S1: AIN0-1 Input Select

These switches control which lines are routed to the ADS1256 AIN0-AIN1 inputs. Table 8 shows the

positions of these switches.

Table 8. AIN0-1 Input Select Switch (S1)

Board Marking Switch Position Input Source AIN0 Connection AIN1 Connection

EXT Left External J1.2 J1.1

REF Middle Reference voltage +2.5V AGND

ZERO Right Zero (shorted to +2.5V +2.5V

reference)

In the EXT position, J1 pins 1 and 2 are connected to the ADS1256 AIN1 and AIN0 pins, respectively. In

the REF position, the reference is connected across the ADS1256 AIN0 and AIN1 pins. In the ZERO

position, both AIN0 and AIN1 are connected to the reference. This configuration gives a zero-scale

reading across AIN0 and AIN1.

The REF and ZERO positions are useful for noise tests.

SBAU090C–November 2003–Revised July 2010 ADS1256EVM and ADS1256EVM-PDK