The AD4858 requires the following five supplies:
V CC and V EE , the positive and negative analog input buffer supplies. VCC should be at least 3.2 V higher than the maximum expected input voltage (INx+ or INx-). VEE should be at least 3.2V lower than the minimum expected input voltage (INx+ or INx-).
V DD , the 5V core supply
V DDH , the internal LDO supply, that should be between 2.2 and 5.25V. Alternatively, the internal LDO can be bypassed so V DDH should be tied to AGND and 1.8 V should be applied to V
V IO , the digital input/output power supply, that should be within 0.9 V and 5.25V
See Power Consideration section of the datasheet for more info.