2.6 - CAL - STB [U12 Datasheet]
These terminals are primarily used at the factory during testing and calibration.
CAL is a precision 2.5 volt reference, and can be used during normal operation, but care should be taken to observe the current limits specified in Appendix A. The CAL pin is protected from ESD and overvoltage, but severe overvoltage (steady-state or transient) can damage CAL, and result in the failure of all analog inputs.
STB has 2 purposes. One is to disable the watchdog as described in Section 4.35, and the other is to create a rectangular output signal for testing. For the latter, if the U12 is streaming the STB frequency matches the sampling frequency, while if not streaming the STB frequency is about 28 kHz. To get this output signal on STB use the enableSTB parameter in the Counter function.