An autozeroing floating-gate bandpass filter [in CMOS]

We have developed a bandpass floating-gate amplifier that uses tunneling and pFET hot-electron injection to set its DC operating point adaptively. Because the gate currents are small, the circuit exhibits a high-pass characteristic with a cutoff frequency less than 1 Hz. The high-frequency cut-off is controlled electronically, as is done in continuous-time filters. We have derived analytical models that completely characterize the amplifier and that are in good agreement with experimental data. This autozeroing floating-gate amplifier demonstrates how to use continuous-time, floating-gate adaptation in amplifier design.