8-bit SAR-ADC with offset calibration

This is a mixed-mode project featuring a 8-bit SAR-ADC, with offset calibration. The logic section is synthesized using the openlane digital flow.

SAR

The adc is composed of a top-plate sampled CDAC, with a capacitor array of mimimum sized MIM caps.

The comparator is a single-stage regenerative comparator, with a MOM array for trimming ADC offset.

Layout

The layout is created using magic as a pcell generator and drc checker, while the connection of the design is done using klayout.

Simulation

The simulation is carried out using ngspice using the mixed-mode xspice capabilities. The digital section is synthesized using yosys that can then be bridged to/from the analog section.

The Schematics are created using xschem, which also serves as the simulation framework.

The simulation output can then be viewed in both analog and digital domain.

Digital waveforms displayed using GTKWave

Analog waveforms displayed using Gnuplot in interactive mode.