CA3080 And LT1228 Based Linear Voltage Controlled Square-Triangular Wave Oscillator

ABSTRACT This paper presents the design and realization of a square/triangular waveform generator based on current-mode design principles using the LT1228 integrated circuit, which internally combines an operational transconductance amplifier (OTA) with a current feedback amplifier (CFA) and a current-mode integrator. The proposed circuit overcomes the limitations of conventional voltage-mode waveform generators, which rely on RC networks and comparators, by utilizing OTAs, a CFA, and an op-amp for both integration and Schmitt trigger functions. The Schmitt trigger, configured using the LT1228 in its saturation region, provides a stable square waveform with electronically adjustable hysteresis through the bias current. The amplitude and duty cycle of the generated waveforms are independently tunable by controlling the input voltages and reference voltage (Vref), offering a flexible and compact solution for voltage and power applications. Experimental results confirm the circuit’s capability to generate waveforms at approximately 10.42 kHz, with duty cycles of 90%, 50%, and 10% by adjusting Vref from -1.6V to 1.6V. The design operates efficiently at ±1V supply, making it ideal for integration into sensor interfaces, waveform generators, modulators, and analog signal processing circuits. Keywords: Current-mode integrator, LT1228, Schmitt trigger, Square/triangular wave generator, Duty cycle control