Analog Negative-Bias-Temperature-Instability Monitoring Circuit

A negative-bias-temperature-instability (NBTI) monitor subcircuit is presented and implemented in 65-nm CMOS technology. The subcircuit can be incorporated in various analog circuit blocks subject to different variability, stress, and aging histories. For an amplifier block, the NBTI monitor is a linear sensor, and sensing is provided as variation of the amplifier gain in response to NBTI-induced bias variation. The monitor sensitivity in this configuration is 3.15 V^-1 and is demonstrated through electrothermal stress on the amplifier circuit.