Ultra Low Power Small Area Active Balun for Low Frequency Biomedical Optical Communication

In interferometry, a transimpedance amplifier (TIA) is used to convert current from a photo-diode into a voltage. The photo-diode current is single-ended and a differential signal is often desirable, however, size and power are often a primary concern. This paper presents a compact and low-power active balun circuit specifically designed for high-level system integration in an interferometry test bench compatible with other optoelectronics circuits. The proposed front-end circuit is laid out and extracted using 65 nm CMOS technology. It operates on a 2.5 V supply with a power consumption of $\approx 700 \mu \mathrm{W}$ and has been validated through comprehensive simulations. The total occupied area of the active balun is $0.001 \text{mm}^{2}$ and the operating frequency is 200 kHz.