A robust to PVT fully-differential amplifier in 45nm SOI-CMOS technology

In this paper the design of a robust to Process, Voltage and Temperature (PVT) variations fully-differential voltage amplifier is presented. The proposed circuit is implemented in a standard digital CMOS technology as 45 nm-1 V Silicon-on-Insulator. The robustness of the circuit is achieved through the use of a novel input stage, which combines two single-ended differential pairs to obtain a fully-differential behaviour. In addition, compound transistors are used in order to increase the output impedance of the devices and hence the gain. As a result, a low-frequency gain of 60 dB is achieved, with a maximum variation of ±4.2 dB for all process corners and temperatures between -40 °C and 120 °C, and supply voltages between 0.9 V and 1.1 V; moreover transient behaviour and PSRR present a robust performance too.