A Chopper-Stabilized Bandgap Reference with a Double-Sampled FIR Filter in 180-nm CMOS

A chopper-stabilized, low-noise bandgap reference (BGR) employing a double-sampled, switched capacitor low pass FIR filter (DS-FIR) is presented. Chopping reduces the low frequency flicker noise, while the FIR filter rejects the high frequency thermal noise. Double-sampling is used to avoid the down-conversion of chopped flicker noise, due to the sampling nature of the switched capacitor filter. Designed in 180-nm CMOS process, the proposed BGR achieves a 5X reduction in flicker noise (at 1 kHz) and 100X reduction in thermal noise (≥ 100 kHz) compared to the basic BGR, with a small area overhead. The entire circuit occupies 0.042 mm
²
at schematic level.