With the continuous intelligentization of power systems, the demand for the integration of digital chips and sensor chips such as the Internet of Things is also increasing. A CMOS lineal magnetic Hall sensor front‐end working in current mode with programmable gain stage is designed and implemented with SMIC 55 nm standard CMOS technology. By using a spinning‐current technique, chopper technique, and digital calibration technique to eliminate the offset voltage and nonlinearity, this magnetic Hall sensor can be easily integrated into digital systems like SoCs. This work has already finished the circuit simulation and layout design, and all simulation indicators basically reach the expected value. The maximum gain of proposed sensor systems can be up to 33.9 dB. The total power is less than 4 mW. And the total area is less than 0.113 μm2. The magnetic Hall sensor can be easily integrated into chips such as the power Internet of Things to form a single‐chip‐level SoC design, which is mainly used in applications such as circuit breakers and electric energy measurement.