A CMOS Soft-Switched Transconductor and its application in filters

Clemens H.J. Mensink

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    This paper presents a transconductor suitable for implementation in sub­micron CMOS technology. The transconductor is nearly insensitive for the second order effects of the MOS transistors, which become more and more prevalent in today’s sub-micron processes. The transconductor relies on a differential pair with variable degeneration resistance, while the degeneration resistors are 'soft-switched’ by means of MOS transistors. The transconductance is continuously tunable. A new device in which the degeneration resistors and 'soft-switches’ are merged is discussed. Besides, a third-order 5.5 MHz low-pass filter has been realized in a 0.5 pm CMOS process using the 'soft-switched’ transconductor. At a 3.3 V supply voltage the filter dissipates 12 mW and the dynamic range equals 62 dB where the THD is -48 dB for an input voltage of 1 Vpp.
    Original languageEnglish
    Pages (from-to)5-13
    Number of pages9
    JournalTijdschrift van het Nederlands Elektronica- en Radiogenootschap
    Issue number1
    Publication statusPublished - 1998

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