Advanced Mixed Signal Concepts Exploiting the Strong Body-Bias Effect in CMOS 22FDX®

Abstract

In this article, an overview of the most recent fully-depleted silicon on insulator technology (FD-SOI) design techniques in the field of mixed-signal circuits and systems are given. Cutting edge performance is achieved by using dynamic as well as static body-biasing techniques. 22FDX <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> is a 22nm CMOS FD-SOI technology providing both, a unique wide-band body-bias tuning range in conjunction with minimized parasitic device loads, due to the significant reduced pn junctions in the signal path. As a result, transistor transit frequencies exceeding 400GHz with improved linearity is achieved. With a linear threshold voltage sensitivity of around 75mV per Volt, 22FDX <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> gives designers a competitive additional degree of freedom. After introducing 22FDX <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> , a 5-bit 18.5GS/s flash ADC is presented utilizing body-biasing to generate accurate threshold voltage offsets within the comparators and thus omitting a power-hungry resistive ladder. Then, dynamic body-biasing is used for a 1.5GS/s track-and-hold circuit to improve the bandwidth while the leakage is reduced obtaining 80dBc SFDR up to the fourth Nyquist zone. Furthermore, a 26GHz ring oscillator is presented, which utilize the strong threshold voltage sensitivity to fully compensate corner dependency. Finally, a body-biasing controlled DAC linearization technique for multi-bit Sigma-Delta modulators enabling 90dBc SFDR, as well as a DAC driver termination impedance control for a 6GS/s 10-bit automotive Ethernet SST-DAC-Driver are presented.