meanwhile even though the same reference resistor array is shared by the first and second channels in the converter of fig1 a single reference resistor array may be shared by two or more channels in a multi channel analog to digital converter in an alternative embodiment of the present invention since the number of comparators is reduced to half of that in prior devices in case of a single channel converter and the number comparators and resistors are further reduced for a multi channel converter because the same reference resistor array is used for all the channels mismatching between comparators and between channels caused by process variations can be significantly reduced compared to the prior devices fig3 is a circuit diagram of a preferred embodiment of the first and second code generators 180 and 182 shown in fig1 according to the present invention in fig3 the code generator includes an inverting unit 208 comprised of first through fourth invertors 200 through 206 a first logic combination unit 218 comprised of first through m 2 1 th and gates 210 through 216 a second logic combination unit 228 comprised of first through m 2 1 th or gates 220 through 226 and a latch unit 230 the code generator shown in fig3 performs a logic operation on the middle code value and the 7 bit half thermometer code output by the first or second channel comparator 190 or 192 of fig1 and converts the result to a 15 bit full thermometer code in fig3 d0 indicates a middle code value output by the first or second channel comparator 190 or 192 and d1 through d7.