I am designing a circuit using HMC980LP4E active bias controller and HMC863ALC4 power amplifier. On the HMC980LP4E, I am using the depletion mode of the amplifier (VNEG = Internal) following figure 34 in the datasheet. I expected VNEG input should be -2.46V as described in table 7 (Mode Selection). But, VNEG is measured as +2.8V. This doesn't make sense. I read both Application note AN-1363 and HMC980LP4E datasheet very carefully, but could not find any clue as to why this is. Could you please give any advice as to what is causing this issue.