Current differencing transconductance amplifier

Current differencing transconductance amplifier (CDTA) is a new active circuit element.

Some voltage and current mode applications using this element have already been reported in literature, particularly from the area of frequency filtering: general higher-order filters, biquad circuits, all-pass sections, gyrators, simulation of grounded and floating inductances and LCR ladder structures.

Nonlinear CDTA applications are also expected, particularly precise rectifiers, current-mode Schmitt triggers for measuring purposes and signal generation, current-mode multipliers, etc.

Here, output terminal currents are equal in magnitude, but flow in opposite directions, and the product of transconductance (

is the external impedance connected to z terminal of the CDTA.

CDTA can be thought as a combination of a current differencing unit followed by a dual-output operational transconductance amplifier, DO-OTA.

denote non-inverting and inverting input voltage of the OTA, respectively.

When this element is used in CDTA, one of its input terminals is grounded (e.g.,