A 0.3-V High Linear Rail-to-Rail Bulk-Driven OTA in 0.13 μm CMOS

A new solution for an ultra-low-voltage (ULV), linear operational transconductance amplifier (OTA) is presented in this brief. The circuit is based on a non-tailed, classAB differential stage, combined with an additional linear resistor, which suppress the third-order harmonic term component, thus providing a highly linear DC transfer characteristic with no extra power consumption. While fabricated in a 0.13 $\mu \text{m}$ CMOS process, and supplied with $\text{V}_{\mathrm{ DD}}$ of 0.3 V, the circuit provides rail to rail input range with THD below 0.5 % for a nominal transconductance of 2.93 $\mu \text{S}$ . The transconductance can be tuned from 1.41 $\mu \text{S}$ to 5.72 $\mu \text{S}$ , with rail-to-rail input swing and THD below 1%. Thanks to its compact structure, the circuit occupies only $935~\mu \text{m}^{2}$ , with transconductance/power ratio of 5.75 $\mu \text{S}/\mu \text{W}$ .