Level-shifter free approach for multi-Vdd SOTB employing adaptive Vt modulation for pMOSFET

Abstract

This paper proposes a level-shifter free (LSF) approach for multi-VDD design to employ a combination of body bias control and a superior threshold-voltage (Vt) modulation capability of SOTB (Silicon on Thin BOX) devices. We applied this approach to a microprocessor test chip with low-voltage (VDDL) and high-voltage (VDDH) domains, and fabricated it in a 65nm SOTB technology. Measurement results demonstrated that the chip correctly operates at VDDL=0.6V and VDDH=1.2V under the reverse-body-bias (RBB) of 2V for pMOS transistors in the VDDH domain while suppressing the static dc current.