IMPROVED NULL CANCELLATION IN A 6th-ORDER Σ-Δ MODULATOR REALIZED WITH TWO 3rd-ORDER SECTIONS |
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| Alan J. Davies, Godi Fischer, Hans-Helge Albrecht, Jürgen Hess |
- Abstract:
- This paper presents an improved rnethod to digitally correct for statit, analog circuit imnperfections in a two-stage, 6th order, cascaded (6-3) sigma-delta modulator. By adding a digital correction term to the output of die digital noise cancellation filter, the first stage parasitic quantization noise due to finite amplifier gain and C-Ratio mismatches can be completely removed. A 6-3 modulator implemented as a fully differential switched-capacitor circuit, designed for an OSR of 16, has heen fabricated in a 1.2 µm double-poly n-well CMOS process. Improvements have been made in the null cancellation leading to approximately a 10 dB increase in SNDR ovor a range of signal amplitudes from 12 µVolts to 500 mV. A peak SNDR/SFDR of 87/100 dB for a 1 MHz sample rate and 84/93 dB for a 2.5 MHz sample rate have heen achieved.
- Download:
- IMEKO-TC4-2002-044.pdf
- DOI:
- -
- Event details
- IMEKO TC:
- TC4
- Event name:
- TC4 Conference and Workshop 2002
- Title:
- 4th International Conference on Advanced A/D and D/A Conversion Techniques and their Applications (together with 7th IMEKO TC4 Workshop on ADC Modelling and Testing)
- Place:
- Prague, CZECH REPUBLIC
- Time:
- 26 June 2002 - 28 June 2002