An Analogue Baseband Chain for a Magnetic Tunnel Junction Based RF Signal Detector

This work presents an analogue baseband (BB) chain for a magnetic tunneling junction (MTJ) based radiofrequency (RF) signal detector fully integrated in a hybrid CMOS-MTJ technology. The BB chain contains a 6 ^th -order $\mathrm{g}_{\mathrm{m}} - \mathrm{C}$ low-pass filter (LPF), a BB amplifier, a comparator, and a current bank. According to measurement results, the 6 ^th -order LPF with a cut-off frequency of 10 MHz consumes a very low DC power of 2.41 mW. Its DC power consumption per pole of 0.4 mW is the lowest among the state-of-the-art LPFs. The LPF can be also switched on and off very fast within 110 ns. With the fast switch-ability and the low power consumption, the LPF outperforms the state of the art. Furthermore, the complete BB chain can transform a 2.5 $\mathrm{mV}_{\mathrm{PP}}, 5$ Mbps BB signal into digital data with a bit error rate fewer than 10 ⁻⁶ . The BB chain consumes 2.85mW including all bias circuits. To achieve power efficiency, the BB chain is designed to operate under an aggressive duty-cycling mode. The switch-on time of the BB chain is within 200 ns.