SLVUAW9C September 2016 – February 2020 UCD90320
For parameters related to output voltage, the UCD90320 supports the linear format defined in Section 8.3.1 of the PMBus specification. The linear format uses a 16-bit unsigned mantissa for each parameter, along with an exponent that is shared by all the voltage-related parameters. The exponent is reported in the bottom 5 bits of the VOUT_MODE parameter.
The voltage value is calculated using the equation
Where:
Voltage is the parameter of interest, in volts,
V is a 16-bit unsigned binary integer mantissa, and
X is the signed 5-bit twos-complement binary integer exponent from VOUT_MODE.
Exception: The PMBus standard assumes that all output voltages are expressed as positive numbers; therefore, all parameters related to output voltage are unsigned integers, with a few notable exceptions. The VOUT_CAL_OFFSET, and VOUT_CAL_MONITOR values are intended for making fine adjustments to the output voltage and may take on small negative values. As such, these parameters are treated as signed twos-complement binary integers.