An inherently linear and compact MOST-only current-division technique

A technique is presented that uses the same MOS transistors for both division and switching functions, eliminating resistors or capacitors. Although an MOS-transistor exhibits a nonlinear relation between the current and voltage (even in the linear region), it is shown that the current division is inherently linear. The most important measurement results are shown. The dynamic range in the audio-band (0-20 kHz) is 103 dB with respect to a maximum input signal of 1 V/sub rms/. At 1 V/sub rms/, THD is below -80 dB over the audio band and below -85 dB under 3 kHz. As the unity-gain frequency of the opamps is 4.5 MHz, the bandwidth of the circuit is limited to 1.5 MHz. Attenuation accuracy is better than 0.15 dB up to -48 dB and better than 0.4 dB over the entire attenuation range.<>