Metal-Oxide-Semiconductor Cascode Mirror Circuit
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
A cascode mirror circuit of the type described by Choy et al entitled "High-Frequency CMOS Switched-Capacitor Filters for Communications Application" in the IEEE Journal of Solid-State Circuits, Vol. SC-18, No. 6, p. 652 et seq, December 1983, is improved by the addition of series resistive impedance, as shown in Fig. 1. (Image Omitted) The circuit in Fig. 1 uses R1 and R2 to introduce negative feedback in order to increase the output impedance of QY. The back-gate bias effect on QX and QY increases their threshold voltages. The output characteristics of the circuit are shown in Figs. 2 and 3, and demonstrate a transfer ratio of 92%. The output impedance of the circuit is about 2.5 times higher than the standard mirror for similarly sized devices. This is due to the local negative feedback.