A Digital Compatible Offset Canceled Latch-Styled Sense Amplifier Used for PUF Sensing

The latch-styled sense amplifier (LSSA) is widely used to amplify the micro-output voltage of a physical unclonable function (PUF) due to its compact size and low cost. However, the offset in LSSA is large, and current methods for offset cancellation struggle to eliminate the offset caused by mismatches of the two input NMOS and two PMOS transistors while maintaining compatibility with both resistive and capacitive inputs. To address this issue, we store the offset introduced by the transistors in the two output capacitors and use two additional input capacitors to isolate the influence of the input signals’ DC voltage. Moreover, all circuits in the offset-canceled (OC) LSSA are constructed using MOS transistors with the minimum allowable length, allowing for the proposed OC LSSA to be easily realized using advanced FinFET processes and integrated into the chip through digital design flow. The proposed OC LSSA is integrated in a switched-capacitor (SC) PUF and fabricated using the 7 nm FinFET process, as well as the 28 nm and 180 nm standard CMOS processes. Test results verify the effectiveness of the offset cancellation method for the LSSA. The bit error rate (BER) across all working environments of the SC PUF using 7 nm, 28 nm, and 180 nm processes decreases from 21.98%, 14.10%, and 7.19% to 7.81%, 4.86%, and 1.88%, respectively, after applying the proposed offset cancellation LSSA to amplify its output voltage.