Design of Low Power and Low Area 12-bit 40MSPS SAR ADCs with a Redundancy Algorithm and Digital Calibration for High Dynamic Range Calorimeter Readout

摘要

We present two versions of 12-bit 40MSPS SAR ADCs using a search algorithm so called generalized redundant. It offers the flexibility to relax the requirements on the DAC settling time. Two more bits of redundancy are included to allow a digital calibration based on a code density analysis to compensate the capacitors mismatching effects. A new monotonic switching algorithm is used for these prototypes, hence 72% of dynamic power consumption is saved in comparison to a conventional switching algorithm. Our first prototype used a non-segmented conservative scheme. The second prototype is segmented and offered a very aggressively low area feature. Both design are fully differential and was produced in a CMOS 130nm 1P8M process. The first design dissipates 11.6mW with an area of 2.63mm~2, while the second dissipate only 6.55mW for an area of only 0.344mm~2 and open the way for multi-channel and multi-gain integrated readout circuits including high resolution converters.