N bits to PPM

\( Y_{ppm} = {1 Million \over 2^N}\ where\ N\ =\ number\ of\ bits \)

			
				bits = 10;
				while bits <= 24
					yppm = f_LSB_ppm(bits);
					fprintf('%1.0f \t %1.2fppm\n', bits, yppm);
					bits = bits + 2;
				end;
			
			
				function [ y_ppm ] = f_LSB_ppm(bits)
				  y_ppm = 1e6/2^bits;
				end
			
		
			
				>>
				10 	 976.56ppm
				12 	 244.14ppm
				14 	 61.04ppm
				16 	 15.26ppm
				18 	 3.81ppm
				20 	 0.95ppm
				22 	 0.24ppm
				24 	 0.06ppm
			
		

If INL for 18-bit ADC is specified at 5 ppm, this means that

\( INL = {5\ ppm \over {3.81\ ppm}} = {1.31\ LSB} \)

References:

  1. National Instruments, Inc. Converting PPM (Parts Per Million) to Number of Bits (LSBs) for INL Specifications
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