Low-Voltage Current Differencing Buffered Amplifier Using Only NMOS Transistors

A circuit realization of a current differencing buffered amplifier (CDBA) in low-voltage operation is presented. The scheme is through the modification of a low-input resistance CCII+ and the proposed CDBA can operate with the minimum supply voltage of plusmn1.25 V. In order that the signal path consists of only NMOS transistors, a negative current mirror using NMOS transistors is employed. With standard 0.5-mum CMOS process parameters, PSPICE simulation results show that the proposed CDBA provides the terminal resistances of
rn
=
rp
=
rw
= 13 Omega,
rz
= 290 kOmega, and
f
-
_3db
cong 3 500 MHz.