Comments on "A parallel A/D converter array structure with common reference processing unit

For the original article see ibid., vol.36, no.8, p.1116-19 (1989). In their paper K. Chen and C. Svensson described a successive approximation technique for an A/D convertor array. The commenters claim that the basic structure of this technique had previously been proposed by them (see Proc. IEEE Int. Symp. Circuits Syst., p.1286-9, May 1986). Also, while the approach is insensitive to the capacitor ratio mismatch, it is not, according to the commenters, insensitive to the finite gain of the amplifiers as claimed.<>