A 1.2-MHz 10-bit Continuous-Time Sigma-Delta ADC Using a Time Encoding Quantizer Articles uri icon

publication date

  • January 2009

start page

  • 16

end page

  • 20

issue

  • 1

volume

  • 56

international standard serial number (ISSN)

  • 1549-7747

electronic international standard serial number (EISSN)

  • 1558-3791

abstract

  • This paper shows the operating principle and experimental results of a new continuous-time sigma-delta modulator architecture. The proposed modulator does not require a multibit quantizer nor a mismatch-shaping digital-to-analog converter to produce a multibit noise-shaped output. Instead, its quantizer encodes the loop filter output in a binary signal using a time encoding technique similar to pulsewidth modulation. This binary signal is used to generate both the analog feedback loop signal and the digital output. A proof-of-concept chip in 0.35-µm CMOS achieves 10 bits of resolution within a signal bandwidth of 1.2 MHz using a first-order modulator.