Embodiments of threshold adjustment circuits are disclosed. An example circuit includes a first differential pair of first and second thin oxide transistors. The first and second thin oxide transistors decrease a DC voltage component of a first and/or second component of an input signal of the circuit. The example circuit further includes a second differential pair of third and fourth thin oxide transistors. The second and third thin oxide transistors increase a DC voltage component of the first and/or the second component of the input signal. The example circuit also includes a power supply that provides a supply voltage to the circuit, the power supply having a voltage level above a reliability level of the thin oxide transistors. In the example circuit, each of the differential pair thin oxide transistors is switched by a signal that keeps each of the first, second, third, and fourth thin oxide transistors operating in saturation.