Aging-sensitive recycling sensors for chip authentication

Various devices, methods and systems are provided for aging-sensitive chip authentication. In one example, among others, a chip includes a reference Schmitt trigger ring oscillator (STRO) configured to enter a sleep mode during operation of the chip; a stressed STRO; a VDD charge pump configured to boost a positive voltage supplied to the stressed STRO during operation of the chip; and/or a GND charge pump configured to under-drive a ground voltage supplied to the stressed STRO during operation of the chip. In another example, a method includes detecting activation of a chip including a reference STRO and a stressed STRO and, in response to the activation of the chip, initiating sleep mode operation of the reference STRO. In response to the activation of the chip, a VDD voltage supplied to the stressed STRO can be boosted and/or a GND voltage supplied to the stressed STRO can be under-driven