This paper presents a large array containing 1600 active electrodes, and the surface electrodes enable amplification in situ by a front-end amplifier under each electrode. In this architecture, the array has the resolution at the level of 400 electrodes per mm 2 due to a special feedback used in each amplifier, which achieves a 38.9dB amplification, an input-referred noise of 5.1 uV within a 2500um 2 area consumption and a power consumption of 1.92uW. Allowing for the multitudinous pixels of the whole array, a modified maximum flow minimum cost (MFMC) algorithm is proposed to give a pattern of connection for all electrodes.