Th. Shu et al., A 13-B 10-MSAMPLE S ADC DIGITALLY CALIBRATED WITH OVERSAMPLING DELTA-SIGMA CONVERTER/, IEICE transactions on electronics, E78C(6), 1995, pp. 691-700
Two key techniques necessary to digitally calibrate multistep or pipel
ined converters are demonstrated in a differential 5-V, 13-b, 10-Msamp
le/s analog-to-digital converter (ADC), One technique, called code-err
or calibration, is to linearize the transfer characteristic of digital
-to-analog converters (DAC's) while the other, called gain-error prora
tion, is to evenly distribute interstage gain errors over the full con
version range, The core of the former technique is an oversampling del
ta-sigma ratio calibrator working synchronously with the converter, Th
is digital calibration process constantly tracks and updates the code
errors without interfering with the normal operation, The prototype co
nverter fabricated using a 1.4-mu m BiCMOS process consumes 360 mW wit
h a 5-V single supply and exhibits a signal-to-noise ratio of 71 dB an
d a maximum end-point integral nonlinearity of 1.8 LSB at a 13-b level
, The proposed techniques can be incorporated into general multistep o
r pipelined ADC's without sacrificing the conversion speed.