A 5kHz Bandwidth Low Noise Chopper-Stabilized Dual-Band Selective Filter SoC
In this paper, various blocks and structures applied to the low-noise 2 band selection band pass filter are described. In the proposed band pass filter when the frequency is input through the buffer, one of Band 1 or Band 2 can be selected using the switch, and the output goes through the buffer after the selected switch among Band 1 and Band 2. After the pre-amplifier, the low frequency band pass filter is used to secure -3 dB or more at 29.5 kHz (5 kHz range) and is used to secure -1 dB or more at 39.5 kHz (5 kHz range). The aim is to remove the interference between bands by -20 dB or more at the interference frequencies of 29.5 Hz and 39.5 Hz, which are the center frequencies of each band. Chopper structure was used to reduce noise, and it was designed to drop more than -21dB/√Hz in Band1,2.