An Ultra-Low Voltage and Low-Energy Level Shifter in 28-nm UTBB-FDSOI

A low-power level shifter capable of up-converting sub-50 mV input voltages to 1 V has been implemented in a 28 nm FDSOI technology. Diode connected transistors and a single-NWELL layout strategy have been used along with poly and back-gate biasing techniques to achieve an adequate balance between the drive strength of the pull-up and pull-down networks. Measurements showed that the lowest input voltage levels, which could be upconverted by the 10 chip samples, varied from 39 mV to 52 mV. Half of the samples could upconvert from 39 mV to 1 V. The simulated energy consumption of the level shifter was 5.2 fJ for an up-conversion from 0.2 V to 1 V and 1 MHz operating frequency.