Design of a Low Voltage Schmitt Trigger in 0.18 um CMOS Process With Tunable Hysteresis

Schmitt triggers are commonly used in communication and signal processing techniques to solve noise problem. A low voltage Schmitt trigger circuit with tunable hysteresis is proposed in this paper. For obtaining hysteresis under low voltage, a cross-coupled static inverter pair is used. By adjusting the symmetrical load operation, the hysteresis of the Schmitt trigger is varied. The cross-coupled inverter pair regenerative operation is controlled by it. Designed in 0.18 um CMOS process technology, the simulation results show that the proposed Schmitt trigger circuit’s triggering voltage can be adjusted approximately 0.5 V to 1.2 V. The proposed design is suitable to be implemented in buffers, sub-threshold SRAMs, retinal focal plane sensors, wireless transponders and pulse width modulation circuits.