Variable resistance memory device and system thereof
A phase-change random access memory device is provided. The phase-change random access memory device includes a global bit line connected to a write circuit and a read circuit, multiple local bit lines, each being connected to multiple phase-change memory cells, and multiple column select transistors selectively connecting the global bit line with each of the multiple local bit lines, each column select transistor having a resistance that varies depending on its distance from the write circuit and the read circuit.
1. A variable resistance memory device comprising:
a memory cell array comprising a plurality of resistance memory cells, the memory cell array being divided into a first area and a second area which are different from each other;
a temperature compensation circuit comprising one or more reference cells;
a data read circuit performing a read operation by supplying a current, which changes according to the resistance of the reference cells, to one or more of the resistance memory cells; and
a write circuit examining data provided by an external source and writing the data to the first area or the second area based on the examination result,
wherein the first area has a shorter response time and a faster access time than the second area.
2. The variable resistance memory device of claim 1 , wherein the data provided by the external source comprises a code, which indicates whether the data should be stored in the first area or the second area, in a data header.
3. A variable resistance memory device comprising:
a memory cell array comprising a plurality of resistance memory cells, the memory cell array being divided into a first area and a second area which are different from each other;
a temperature compensation circuit comprising one or more reference cells; and
a data read circuit performing a read operation by supplying a current, which changes according to the resistance of the reference cells, to one or more of the resistance memory cells,
wherein the first area has a shorter response time and a faster access time than the second area, and
wherein the memory cell array is divided into a plurality of memory banks, each being divided into a plurality of memory blocks, and wherein the reference cells are disposed in each memory bank or each memory block.
4. A variable resistance memory device comprising:
a memory cell array comprising a plurality of resistance memory cells, the memory cell array being divided into a first area and a second area which are different from each other;
a temperature compensation circuit comprising one or more reference cells;
a data read circuit performing a read operation by supplying a current, which changes according to the resistance of the reference cells, to one or more of the resistance memory cells;
a global bit line connected to a write circuit and a read circuit;
one or more local bit lines coupled to resistance memory cells which are disposed in the second area; and
a plurality of column select transistors, each selectively connecting the global bit line to any one of the local bit lines,
wherein the first area has a shorter response time and a faster access time than the second area.
5. The variable resistance memory device of claim 4 , wherein the resistance of a column select transistor located farther from the write circuit and the read circuit is smaller than that of a column select transistor located closer to the write circuit and the read circuit.
6. The variable resistance memory device of claim 5 , wherein the column select transistor located farther from the write circuit and the read circuit is larger than the column select transistor located closer to the write circuit and the read circuit.
7. The variable resistance memory device of claim 5 , wherein a doping concentration of a channel region of the column select transistor located farther from the write circuit and the read circuit is higher than that of a channel region of a column select transistor located closer to the write circuit and/or the read circuit.
8. A memory system comprising:
a variable resistance memory device; and
a memory controller accessing the variable resistance memory device in response to an external command,
wherein the variable resistance memory device comprises:
a memory cell array comprising a plurality of resistance memory cells and being divided into a first area and a second area;
a temperature compensation circuit comprising one or more reference cells;
a data read circuit performing a read operation by supplying a current, which changes according to the resistance of the reference cells, to one or more of the resistance memory cells; and
a write circuit examining data provided by an external source and writing the data to the first area or the second area based on the examination result,
wherein the first area has a shorter response time and a faster access time than the second area.