The open-drain DIAG pin can be
monitored to confirm the device is operational, and the output voltage is valid.
During power-up, the DIAG pin is actively held low until the high-side supply is in
regulation and the device operates properly. The DIAG pin is actively pulled low
if:
- The low-side does not receive data from the high-side (for
example, because of a loss of power on the high-side). The amplifier outputs are
driven to negative full-scale.
- The high-side DC/DC output voltage (DCDC_OUT) or the high-side
LDO output voltage (HLDO_OUT) drop below their respective undervoltage detection
thresholds VDCDCUV and VHLDOUV as sepecified in the
Electrical Characteristics table. In this case, the low-side may still receive
data from the high-side but the data may not be valid. The amplifier outputs are
driven to negative full-scale.
During normal operation, the DIAG pin
is in a high-impedance state. Connect the DIAG pin to a pull-up supply through a
resistor or leave open if not used.