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Built-In Test and Calibration of DAC/ADC Using A Low-Resolution Dithering DAC. Wei Jiang and Vishwani D. Agrawal Electrical and Computer Engineering Auburn University 17th IEEE North Atlantic Test Workshop. Outline. Overview Test of DAC Polynomial fitting algorithm
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Built-In Test and Calibration of DAC/ADC Using A Low-Resolution Dithering DAC Wei Jiang and Vishwani D. Agrawal Electrical and Computer Engineering Auburn University 17th IEEE North Atlantic Test Workshop
Outline • Overview • Test of DAC • Polynomial fitting algorithm • DAC calibration by dithering DAC • Test and calibration of ADC • Simulation results • Summary The 17th IEEE North Atlantic Test Workshop’08
Overview • Built-in test solution for mixed-signal system-on-chips (SoCs) • Testing and characterizing non-linearity of on-chip DAC/ADCs • Output calibration and error compensation for better linearity • Low cost for design and manufacturing The 17th IEEE North Atlantic Test Workshop’08
Typical Mixed-signal SoC The 17th IEEE North Atlantic Test Workshop’08
Non-linearity Errors INL error INL error The 17th IEEE North Atlantic Test Workshop’08
Proposed BIST Scheme Lineardigital code outputs Linearanalog outputs The 17th IEEE North Atlantic Test Workshop’08
Third-Order Polynomial Fitting • Proposed by S.K. Sunter in ITC’96 • Divide DAC transfer function into four sections • Combine function outputs of each section (S0, S1, S2, S3) • Calculate four coefficients (b0, b1, b2, b3) by easily-generated equations The 17th IEEE North Atlantic Test Workshop’08
Test of On-Chip DAC Fitting for INL error The 17th IEEE North Atlantic Test Workshop’08
Design of ΣΔ Modulator 3 LSB 104.10dB The 17th IEEE North Atlantic Test Workshop’08
Simulation Results for On-Chip DAC On-chip DAC INL error Polynomial fitting for INL error Fitting results through 6-bit dithering DAC Final analog outputs by calibrated DAC The 17th IEEE North Atlantic Test Workshop’08
Test of On-Chip ADC INL error Calibrated DAC to generate linear analog output The 17th IEEE North Atlantic Test Workshop’08
Summary • A built-in test and calibration scheme for on-chip DAC/ADC is proposed • A polynomial fitting algorithm is used to fix non-linearity error of DAC/ADC outputs • Fault tolerance factor can be chosen for different applications • Simulation results show that linearity is significantly improved after calibration • Future research work: • Reduce the testing time • Improve the fitting algorithm for even higher linearity The 17th IEEE North Atlantic Test Workshop’08
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