Low-voltage digitally controlled current differencing buffered amplifier and its application

In this paper, a design of a low-voltage digitally controlled current differencing buffered amplifier (DC-CDBA) is introduced. The realization scheme is through the cascade connection of a current differencing circuit, a current division network (CDN) and a buffered voltage amplifier. To achieve the digital control of the current gain of the circuit, a novel CDN is also proposed. The proposed DC-CDBA can operate with the low supply voltage of ±1.25V. PSPICE simulations using standard 0.5-μm0.5-μm CMOS process parameters are in agreement with the theory. An application example using the proposed DC-CDBAs as active elements in the realization of the digitally tuned current-mode universal filter is also included.