A method and system for testing a semiconductor memory device applies defined test voltages to a semiconductor memory device in a manner that minimizes a time lapse during shifting from one voltage level to another or one voltage range to another. The system includes registers for storing codewords. Each codeword represents a discrete voltage level. The registers have inputs and outputs. Digital-to-analog converters are coupled to the outputs of the registers for converting a codeword into a corresponding analog voltage with a discrete voltage level. A multiplexer derives a test output voltage from the analog voltage, an external voltage, or both. A mode controller controls the multiplexer to derive the test output voltage. The test output voltage is compliant with defined voltage ranges associated with corresponding modes.