8.2.2.1 Voltage Output Mode

In voltage output mode (M1 and M2 are connected low or left unconnected), the feedback loop through the IA provides high impedance remote sensing of the voltage at the destination, compensating the resistance of a protection circuit, switches, wiring, and connector resistance. The output of the IA is a current that is proportional to the input voltage. This current is internally routed to the OPA summing junction through a multiplexer, as shown in Figure 41.

A 1:10 copy of the output current of the OPA can be monitored at the I_MON pin. This output current and the known output voltage can be used to calculate the load resistance or load power.

During an output short-circuit or an overcurrent condition the XTR305 output current is limited and EF_LD (load error, active low) flag is activated.

Figure 41. Simplified Voltage Output Mode Configuration

Applications not requiring the remote sense feature can use the OPA in stand-alone operation (M1 = high). In this case, the IA is available as a separate input channel.

The IA gain can be set by two resistors, R_GAIN and R_SET (Equation 1):

Equation 1.

or when adding an offset, V_REF, to get bidirectional output with a single-ended input shown in Equation 2:

Equation 2.

The R_SET resistor is also used in current output mode. Therefore, it is useful to define R_SET for the current mode, then set the ratio between current and voltage span with R_GAIN.