Apple Inc.
Hybrid digital-to-analog converter non-linearity calibration

Abstract:

Systems, apparatuses, and methods for performing hybrid non-linearity correction for a digital-to-analog converter (DAC) are described. A circuit includes two correction LUTs, an edge-trim DAC, and a DAC core. A lookup of a first correction LUT is performed using a portion of the most significant bits (MSBs) of a received digital input value. A first correction value, retrieved from the first correction LUT, is applied to the digital input value to generate a corrected value. The corrected value is provided to the DAC core and to a second correction LUT. A second correction value, retrieved from the second correction LUT, is compared to the first correction value. If the second correction value is different from the first correction value, the difference is provided to the edge-trim DAC to generate an analog correction which is applied to an analog output of the DAC core.