Excellent knowledge of:
Focus 1 : LDOs, Charge-Pump supplies, bandgap and bias circuits.
Focus 2 : Switched-capacitor circuits, OPAMPs.
Good knowledge of feedback and compensation techniques.
Good knowledge of precision analog circuit design techniques.
Strong device physics knowledge as it applies to analog IC designs.
Good knowledge of following measurement equipment: spectrum analyzers, oscilloscopes, signal generators.
Better to have knowledge of low noise circuit design; Matlab / Verilog A modeling; experience of display IC design.