A 5-V Switch for Analog Multiplexers With 2.5-V Transistors in 28-nm CMOS Technology

Despite the scaling of the supply voltage of deep-submicrometer CMOS technologies, many applications still require to deal with off-chip signals in high-voltage domains (e.g., 3.3 and 5 V). Hence, foundries offer fabrication processes with voltage-tolerant transistors, which are inherently protected from the electrical stress, at the expenses of compromising their performances, reducing the design portability, and augmenting the production costs in case of the customization of the process. As an alternative, circuit techniques, such as cascoding, adaptive biasing, and voltage shifting, result effective in designing analog circuits, such as amplifiers and voltage drivers at high supply voltage with voltage-scaled transistors. This article presents the architecture of a switch for analog multiplexers (MUXs) able to handle signals up to twice the nominal supply voltage of the employed transistors. To validate the circuit choice, a switch for a 5-V MUX has been designed with 2.5-V transistors in 28-nm CMOS technology. The comparison with a benchmark architecture with tailored 5-V devices shows that an about three times larger area and 4- μ A static current demand have to be considered. Moreover, an accelerated degradation test (ADT) showed a similar decay of the features of both types of switches.