A/D conversion method in high density multilevel non-volatile memory devices and corresponding converter device

摘要

The invention relates to an analog-to-digital conversion method and relevant device, in high-density multilevel non-volatile memory devices. The method applies to multilevel memory cells comprising a floating gate transistor with drain and source terminals; the cell to be read is subjected to a reading operation by applying predetermined bias voltage values to its drain and source terminals, while to its drain terminal is applied a predetermined current value (Iref), and by measuring the value of its gate voltage (Vg). The method of the invention comprises a first conversion phase the most significant bits (MSB) contained in the memory cell, followed by a second conversion phase of the least significant bits (LSB). The first step is completed within a time gap (T1-T0) which corresponds to the rise transient of the gate voltage signal (Vg), while the second step is started at the end of the transient.