Power and performance comparision of body bias in 28HPC and back bias in 22FDX

Abstract

In this paper, the body bias in 28nm Bulk and the back bias in 22nm FDSOI are analyzed and compared from two aspects: power consumption and circuit performance. Taking a 65-stage ring oscillator (RO) with 4-level frequency divider as an example, transistor lengths are all set to 30nm, post simulation results show that, for 22FDX RO, the operating frequency can adjust from 57.8MHz to 206MHz, with the operating current varies from 24uA to 91uA; while for 28HPC, the bulk RO can only modulate the operating frequency from 92.8MHz to 127MHz, with the operating current varies from 67.8uA to 129uA. Therefore, from both view of power and performance, the adjust ability of 22FDX circuits with back bias are much stronger than that of 28HPC circuits with body bias.