Device for reading nonvolatile memory cells, in particular analog flash memory cells

摘要

The reading device (1) comprises an A/D converter (8) of n+m bits receiving an input signal (V1) correlated to the threshold voltage (VTH) of the memory cell (2), and supplying a binary output word (WT) of n+m bits. The A/D converter (8) is of a double conversion stage type (8), wherein a first A/D conversion stage (10) carries out a first analog/digital conversion of the input signal (V1), to supply at the output a first intermediate binary word (W1) of n bits, and the second A/D conversion stage (16) can be activated selectively to carry out a second analog/digital conversion of a difference signal (VD) correlated to the difference between the input signal (V1) and the value of the first intermediate binary word (W1). The second A/D conversion stage (16) generates at the output a second intermediate binary word (W2) of m bits supplied, with the first intermediate binary word (W1), to an adder (20) generating the binary output word (WT) of n+m bits. <IMAGE>