IC Layout

Fig. 1: 24GHz FMCW Radar Interface Layout


The layout of the mixer is made centroid and interdigitated to reduce the effect of process variability. This ensured the reduction of offsets and even order distortions. The LO signals going into the mixer are buffered using FO4 to ensure fast rise times and turn on of the MOSFETs.

Fig. 2: Mixer Layout

8-bit Current-Steering DAC

The selection of the current source and switch array structure as well as their layout presents a challenge in the DAC design. Components values are scaled from a size of A (unit size), then 2*A, 4*A, 8*A, 16*A, 32*A, 64*A, and ultimately 128*A. The elements are arranged using the common centroid matching method.

Fig. 3: 8-bit Current-Steering DAC Layout

Fig. 4: Switch Array Placement

Fig. 5: Current Source Array Placement

8-bit SAR ADC

Common centroid matching is also used in the layout of the ADC's capacitor array.

Fig. 6: 8-bit SAR ADC Layout

Fig. 7: Capacitor Array Placement

Fig. 8: StrongArm Comparator Layout

Fig. 9: Bootstrap Switch & StrongArm Comparator Layout

Zero-Crossing Counter

Fig. 10: Zero-Crossing Counter Layout (APR Generated)

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