JAJSIR7C October 2019 – August 2021 TPS8804
PRODUCTION DATA
The built-in CO connectivity test function connects to the PREF pin and is available when the photo amplifier is not referenced to PREF. The COTEST_EN and COTEST_DIR register bits program a pull-up and pull-down switch on PREF. A 200 kΩ pull-up resistor charges the 1 µF capacitor when the CO test is not in use. When PREF is pulled low, charge is injected into the amplifier and the output pulse shape can be used to determine if the sensor is connected. An external MOSFET and pull-up resistor achieves the same function as the internal COTEST circuitry.