Alternate Hardware Configurations
9
SLAU726 – August 2017
Copyright © 2017, Texas Instruments Incorporated
DAC90x Evaluation Module
3
Alternate Hardware Configurations
This section describes alternate hardware configurations in order to achieve better results or to more
closely mimic the system configuration.
Figure 6. Reconfiguration Hardware Location
3.1
Control Modes
The INT/EXT, REF
in
and FSA pins of the DAC904, DAC902, DAC900, and DAC908 control various DAC
features and functions. This section describes the function of these pins.
3.1.1
FSA Input Pin
For an output current of 20 mA, the potentiometer R14 value is typically set to 2 k
Ω
. Owing to the fact that
the maximum full-scale current is 20 mA when IOUT1 and IOUT2 are terminated into 50-
Ω
load resistors,
the voltage at J8 and J9 is 1 V.
3.1.2
INT/EXT Pin
The internal 1.2-V Vref is selected when the INT/EXT pin is grounded (W3 pins 2 and 3 shorted). When
the INT/EXT pin is tied to 5 V ( W3 pins 2 and 3 shorted) and the W4 jumper is in place, the external 1.2-V
Vref is selected.
