a memory cell array including a plurality of memory cells;

an address decoder configured to decode a row address and a column address from an address signal;

a first voltage generator configured to generate a word line operating voltage for each word line of the memory cell array according to the decoded row address;

a second voltage generator configured to generate a bit line operating voltage of the memory cell array according to the decoded column address;

a page buffer circuit configured to activate according to the bit line operating voltage and to store data to be stored in or read from at least one memory cell; and

a temperature unit configured to determine, from a temperature range table storing a plurality of selection signals mapped to each of a plurality of temperature ranges, a temperature range for a temperature code according to a real-time temperature of the memory cell array, and to adjust a power supply voltage of at least one of the first or second voltage generator based on a selection signal mapped to the determined temperature range,

wherein the temperature unit includes a digital temperature sensor configured to measure a temperature state of the nonvolatile memory device in real time and to output the measured temperature state as the temperature code, and

wherein the power supply voltage is linearly adjusted for each of the plurality of temperature ranges such that the adjustments are represented by a corresponding coefficient, of a plurality of coefficients, and a corresponding intercept, of a plurality of intercepts, for each of the plurality of temperature ranges and such that the adjustments change between temperature ranges,

the plurality of coefficients respectively corresponding to the plurality of selections signals,

the corresponding coefficient selected based on the selection signal mapped to the determined temperature range,

the plurality of intercepts respectively corresponding to the plurality of selection signals, and

the corresponding intercept selected based on the selection signal mapped to the determined temperature range.