Apparatus, systems and methods for for digital testing of adc/dac combination

A method, comprising:

• coupling a digital to analog converter (DAC) an analog to digital converter (ADC) via at least one analog line;
• applying a code pattern having a plurality of sequential values to the digital to analog converter;
• switching a plurality of built-in test switches to couple at least one tap voltage from the DAC to a test bus and to couple a variable reference input voltage to the ADC;
• receiving at a test controller an output signal from the ADC and DAC resulting from application of the code pattern to the DAC and control of the plurality of built-in test switches;
• wherein the test controller is capable of configuring the plurality of built-in test switches between a test-mode operation and a normal-mode operation.

A semiconductor die comprising:

• a digital to analog converter (DAC) comprising a plurality of resistors configured in a resistor string, a plurality of switches connected to the plurality of resistors, and decoder logic adapted to control the plurality of switches based on a code pattern to generate at least one tap voltage;
• an analog to digital converter (ADC) comprising a plurality of comparators to receive at least one tap voltage from the digital to analog converter and a variable reference input voltage;
• on-die circuitry capable of enabling the use of one tap voltage as an input to the plurality of comparators and to disconnect the plurality of comparators from an input voltage to be digitized;
• wherein the digital to analog converter and the analog to digital converter are coupled to a test controller via a test bus;
• and wherein the test controller is capable of configuring the on-die circuitry between a test-mode operation and a normal-mode operation.