Analog Evaluation
8
SLVUBT6A – October 2019 – Revised May 2020
Copyright © 2019–2020, Texas Instruments Incorporated
Using the TPS8804EVM
Figure 7. CO Amplifier Output with Sensor and Calibration Gas
3.1.1
CO Connectivity Test
A simple test confirms that the CO sensor is connected to the EVM. Remove the shunt connected to J7
and connect a shunt to J15 and J16. Write COTEST_EN = 1 and measure the pulse shape on
AMUX_BUF using an oscilloscope. When COTEST_EN = 1, the PREF pin is pulled low and injects charge
into the CO sensor and amplifier. The AMUX pulse shape is different if the CO sensor is disconnected.
Write COTEST_EN = 0, remove the J15 and J16 shunts, and connect the J7 shunt when finished.
