A CMOS 0.8- µm transistor-only 1.63-MHz switched-current bandpass ΣΔ modulator for AM signal A/D conversion
This paper presents a CMOS 0.8-/spl mu/m switched-current (SI) fourth-order bandpass /spl Sigma//spl Delta/ modulator (BP-/spl Sigma//spl Delta/M) IC capable of handling signals up to 1.63 MHz with 105-bit resolution and 60-mW power consumption from a 5-V supply voltage. This modulator Is intended f...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2000 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/3574 |
| Acceso en línea: | http://hdl.handle.net/10261/3574 |
| Access Level: | acceso abierto |
| Palabra clave: | Analog-to-digital conversion ΣΔ modulation Switched-currentΔΣ |
| Sumario: | This paper presents a CMOS 0.8-/spl mu/m switched-current (SI) fourth-order bandpass /spl Sigma//spl Delta/ modulator (BP-/spl Sigma//spl Delta/M) IC capable of handling signals up to 1.63 MHz with 105-bit resolution and 60-mW power consumption from a 5-V supply voltage. This modulator Is intended for direct A/D conversion of narrow-band signals within the commercial AM band, from 530 kHz to 1.6 MHz. Its architecture is obtained by applying a low-pass-to-bandpass transformation (z/sup -1//spl rarr/-z/sup -2/) to a 1-bit second-order low-pass /spl Sigma//spl Delta/ modulator (LP-/spl Sigma//spl Delta/M). The design of basic building blocks is based upon a detailed analysis of the influence of SI errors on the modulator performance, followed by design optimization. Memory-cell errors have been identified as the dominant ones. In order to attenuate these errors, fully differential regulated-folded cascode memory cells are employed. Measurements show a best SNR peak of 65 dB for signals of 10-kHz bandwidth and an intermediate frequency (IF) of 1.63 MHz. A correct noise-shaping filtering is achieved with a sampling frequency of up to 16 MHz. |
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