Compact Sub-Hertz OTA-C Filter Design With Interface-Trap Charge Pump Academic Article uri icon


  • Single-ended and differential operational transconductance amplifier (OTA) configurations are biased with MOSFET interface-trap charge-pumping (ITCP) current generators to achieve very low transconductances for tunable sub-hertz operational transconductance amplifier-capacitor (OTA-C) filter implementation. This paper reviews the basics of ITCP current generation and presents the transconductors and the OTA-C filter configurations based on these transconductors. One of the filters is a low-pass with an experimentally determined lowest cutoff frequency of 0.18 Hz, and the other is a fully differential bandpass with individually tunable lower and upper cutoff frequencies measured down to 0.3 Hz. The former has one 15-pF filter capacitor, and measures 0.0346 mm2, whereas the latter contains four such capacitors and occupies 0.188 mm2silicon. Experimental evaluation also includes offset, harmonic distortion, and noise performance.

author list (cited authors)

  • Becker-Gómez, A., Çilingiroğlu, U., & Silva-Martínez, J.

citation count

  • 8

publication date

  • June 2003