A CMOS transconductance amplifier architecture with wide tuningrange for very low frequency applications |
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Authors: | Veeravalli A. Sanchez-Sinencio E. Silva-Martinez J. |
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Affiliation: | Texas Instrum. Inc., Dallas, TX; |
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Abstract: | A pseudodifferential CMOS operational transconductance amplifier (OTA) with wide tuning range and large input voltage swing has been designed for very small GM's (of the order of a few nanoamperes per volt). The OTA is based on a modified four-quadrant multiplier architecture with current division. A common-mode feedback circuit structure has been proposed and designed using floating-gate transistors to handle large differential signals. Large on-chip capacitors are emulated through impedance scaling circuits. The circuits, fabricated in a 1.2-μm CMOS process, have been used to design a fourth-order bandpass filter and a relaxation oscillator. Experimental results are in good agreement with the theoretical results |
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