ADE9000 – Current channels drifting 853–1127 ppm/°C while voltage channels remain stable

The ADC are identical for Voltage and current. Can you show how the current sensor is connected to the current channel ADC from sensor to ADC inputs. Are you grounding one side of the current sensor? Have you measured the ADC inputs to see if it is drifting over temp?

in technical Ref manual UG-1098 (Rev.A) pg 5   The center tapped burden fixes the common mode to 0.

Another option is single ended. This requires one leg to be grounded to fix the common mode to 0.

Dave

Dave, the fix worked perfectly. Here are the results:

Before (floating common mode):

• Current channels drift: 853–1127 ppm/°C
• Voltage channels: stable

After (6 × 10kΩ resistors from each CT output pin to AGND):

• All three current channels: ~18.4 ppm/°C
• Full temperature sweep from 15°C to 30°C
• All three phases consistent and stable

The measured system drift of 18.4 ppm/°C is well within the ±25 ppm/°C maximum specified in the datasheet, and this figure includes the entire signal chain — ADE9000, voltage dividers, and current sensors.

The root cause was exactly what you pointed out: the HIOKI 9660 CT outputs are floating, with no common mode reference to AGND. Without the center tap, the PGA input bias current interacted with temperature, causing the drift exclusively on the current channels while the voltage channels remained stable.

Two weeks of investigation, two ADE9000 units tested, and the fix was six resistors. Thank you for your guidance — we would not have found it without your expertise.

Dave, the fix worked perfectly. Here are the results:

Before (floating common mode):

• Current channels drift: 853–1127 ppm/°C
• Voltage channels: stable

After (6 × 10kΩ resistors from each CT output pin to AGND):

• All three current channels: ~18.4 ppm/°C
• Full temperature sweep from 15°C to 30°C
• All three phases consistent and stable

The measured system drift of 18.4 ppm/°C is well within the ±25 ppm/°C maximum specified in the datasheet, and this figure includes the entire signal chain — ADE9000, voltage dividers, and current sensors.

The root cause was exactly what you pointed out: the HIOKI 9660 CT outputs are floating, with no common mode reference to AGND. Without the center tap, the PGA input bias current interacted with temperature, causing the drift exclusively on the current channels while the voltage channels remained stable.

Two weeks of investigation, two ADE9000 units tested, and the fix was six resistors. Thank you for your guidance — we would not have found it without your expertise.