This article presents a 15-channel orthogonal code
chopping instrumentation amplifier (OCCIA) for an areaefficient
and low gain-mismatch multi-channel bio-signal acquisition.
Orthogonal codes directly modulate each channel and merge
into a single signal for sharing IA, while performing dynamic
offset compensation with low power consumption. Digitizationbefore-
demodulation (DBD) transmits the combined modulated
data directly, which alleviates ripple noise, and completely
removes the demodulation and TX encoding overhead from
the ASIC. The proposed OCCIA in 0.18-μm 1P6M CMOS,
when compared with the recent multi-channel instrumentation
amplifiers (IAs), shows the smallest area (0.019 mm2/Ch.), low
gain mismatch (0.43%), with the lowest power consumption
(1.97 μW/Ch.) and low crosstalk (< −51.5 dB) at 490-Hz
bandwidth.
Index Terms—Bio-signal acquisition, demodulation-beforedigitization
(DBD), instrumentation amplifier (IA), low mismatch,
orthogonal code chopping (OCC).
Researcher/Author: Jeong Hoan Park, Tao Tang, Lian Zhang, Kian Ann Ng, Gil Gerald Lasam Gammad, Shih-Cheng Yen, and Jerald Yoo