During power up in the DIAGNOSTICS state, the LDC5072-Q1 undergoes a number of self-diagnostics and checks (for
fault thresholds refer to Diagnostics and for de-glitch times refer to Switching Characteristics ):
- EEPROM CRC check: the LDC5072-Q1 calculates the
CRC value of the EEPROM register settings and compares it to the recorded
expected CRC value. In case of FAULT, the LDC5072-Q1 transitions
to the DISABLED state.
- LBIST check: the LDC5072-Q1 undergoes automated
self-testing pattern for the digital logic. In case of FAULT, the LDC5072-Q1 transitions to the DISABLED state.
- ABIST check: the LDC5072-Q1 undergoes automated
self-testing pattern for the fault-monitoring circuits. In case of FAULT, the
LDC5072-Q1 transitions to the DISABLED state.
- Sensor interface BIST check: the LDC5072-Q1
applies the automated test patterns to Sensor interface (LCIN, LCOUT, IN0P,
IN0N, IN1P, and IN1N) pins to check that they are open or shorted to GND or
battery. It also checks if there is a short between the coils of the sensor and
if any of the coils are open. The LDC5072-Q1 will also check if any impedance is present as
specified by the RAGC_EN_AUTO or RPU_AGC_EN on the
AGC_EN pin and check if the AGC_EN pin is not shorted to GND.
- VREG cap loss check: the LDC5072-Q1 uses the
VREG cap to compare the internal time constant with the external time constant
(5-V VCC mode only). This check is only performed at power up and is not
performed if the device transitions from FAULT state to DIAGNOSTICS state. The
maximum capacitance on VREG pin that can trigger this fault is given by
CLOSS_VREG.
- The LDC5072-Q1 enables the LC oscillator and
checks that VUVL_AMP_LC, VOVH_AMP_LC,
VUVL_CM_LC, and VOVH_CM_LC faults disappear within
tLC_FLT_DT.
- The LDC5072-Q1 enables the AFE, AGC, and Output
stages in a staggered manner.
- The LDC5072-Q1 the
device resets all checks and faults for certain period of time to allow all
internal signals to settle and then starts monitor faults
- The LDC5072-Q1 transitions to the Normal state
ensuring that tPRWR_ON is met and no other faults are detected. In
AUTO AGC mode, the LDC5072-Q1 also checks that the output of the
AGC block is within AGC_Target. If the AGC block is not within AGC_Target, the
devices transitions to the DISABLED state.