A 6th order Butterworth SC low pass filter for cryogenic applications from −180°c to 120°c

This paper presents a sixth order Butterworth switched capacitor (SC) low pass filter with radiation-hardened-by-design (RHBD) for cryogenic applications. Implemented in a 0.5μm SiGe BiCMOS technology, this cryogenic SC filter is capable of operating over an ultra-wide temperature (UWT) range from −180°C to 120°C and under high-energy particle radiation environment on the lunar surface. This is the first SC filter, operating over 300#x00B0;C temperature range with RHBD, reported so far. The measured results show that the filter approximates a sixth order Butterworth filter response in range of −180°C to 120°C. The clock-to-cutoff frequency ratio is 100:1. The clock feedthrough is less than 10uV
RMS
with single 3.3V supply. It consumes only 640uA at 200 kHz clock frequency current and occupies only 0.4×1.4 mm
²
.