EVM Setup and Operation
7
SLDU031 – December 2017
Copyright © 2017, Texas Instruments Incorporated
PGAxxxEVM-037 Pressure Sensor Signal Conditioner Evaluation Module
3.2
VDD Voltage Setup
The OWI circuitry can be sensitive to component variances and loading. To ensure proper voltage levels,
a 10-k
Ω
potentiometer (R21) must be adjusted by the user. The potentiometer is located on the bottom of
the board (pictured in
) and should be adjusted while the PGAxxxEVM-037 is powered up first by
pulling the OWI_5P5 pin high with the
EVM Pin State
controls in the GUI (see
), then by
monitoring the voltage on the VDD test point or with the
Voltage Monitor
tab (see section
)
and turning the potentiometer until VDD is between 4.5 V and 5.5 V.
Figure 5. VDD Voltage Adjustment Potentiometer
3.3
Pressure Inputs
The PGAxxxEVM-037 includes a resistive bridge emulator designed to simulate a typical 5-k
Ω
pressure
sensor topology. The variable leg consists of a digital potentiometer in parallel with a 2.61-k
Ω
resistor, and
the parallel components are in series with a 2.55-k
Ω
resistor as shown in
