Step-Down Converter With Stacked Core Transistors for the Innermost Layers of High-Luminosity High-Energy Physics Experiments

Abstract

This article presents a dc/dc converter that is built with stacked transistors in the power stage and is designed to operate at very high switching frequencies of 100 MHz. The converter can be powered with input voltages of 4.8 V and is capable of powering readout electronics with a voltage conversion factor of 4 in close proximity to the LHC beamline. The high switching frequency enables the use of small inductances of only 22 nH while delivering a maximum load current of 1 A. In addition, this article outlines linear regulators featuring stacked pass devices, designed for operation at supply voltages of up to 5.5 V. Notably, both circuits use thin gate-oxide transistors to mitigate the impact of total ionizing dose (TID). While thin gate-oxide transistors are typically used in applications with low supply voltages, transistor stacking is implemented to enable operation at higher input voltages. TID tolerance of up to 1 Grad(SiO2) has been demonstrated for the dc/dc converter and 610 Mrad(SiO2) for the linear regulators with stacked pass devices.