Multi-chip package semiconductor memory device providing active termination control
A semiconductor memory device having a multi-chip package structure providing active termination control. The semiconductor memory device includes first and second memory chips sharing a data I/O bus. The first memory chip includes a first chip enable (CE) port determining whether the first memory chip is activated, and a second CE port monitoring whether the second memory chip is activated. An active termination unit is turned ON only when the first and second chips are deactivated.
1. A multi-chip package (MCP) semiconductor memory device receiving first and second chip enable (CE) signals and comprising:
a first memory chip comprising a first CE port configured to receive the first CE signal, a second CE port configured to receive the second CE signal, and an active termination unit associated with a data input/output (I/O) bus, wherein the first memory chip is activated/deactivated in response to the first CE signal and configured to provide data to the data input/output (I/O) bus via the active termination unit; and
a second memory chip comprising a CE port configured to receive the second CE signal, wherein the second memory chip is activated/deactivated in response to the second CE signal and configured to provide data to the data input/output (I/O) bus,
wherein the active termination unit in the first memory chip is turned ON only when both of the first and second memory chips are deactivated, as indicated by the first and second CE signals received at the first and second CE ports of the first memory chip, respectively.
2. The semiconductor memory device of claim 1 , wherein the activated/deactivated state of the first memory chip is determined by a state of the first CE signal received at the first CE port.
3. The semiconductor memory device of claim 1 , wherein the activated/deactivated state of the second memory chip is determined by a state of the second CE signal received at the CE port.
4. The semiconductor memory device of claim 1 , wherein the second CE signal is provided to the second CE port of the first memory chip and the CE port of the second memory chip via a common CE signal line.
5. A memory system comprising:
a controller configured to provide first and second chip enable (CE) signals to a first multi-chip package (MCP) semiconductor memory device, wherein the first MCP semiconductor memory device comprises:
a first memory chip comprising a first CE port configured to receive the first CE signal, a second CE port configured to receive the second CE signal and an active termination unit, wherein the first memory chip is activated/deactivated in response to the first CE signal and configured to provide data to a data input/output (I/O) bus via the active termination unit; and
a second memory chip comprising a CE port configured to receive the second CE signal, wherein the second memory chip is activated/deactivated in response to the second CE signal and configured to provide data to the data input/output (I/O) bus,
wherein the active termination unit is turned ON only when both of the first and second memory chips are deactivated, as indicated by the first and second CE signals received at the first and second CE ports of the first memory chip, respectively.
6. The memory system of claim 5 , wherein the activated/deactivated state of the first memory chip is determined by a state of the first CE signal received at the first CE port.
7. The memory system of claim 5 , wherein the activated/deactivated state of the second memory chip is determined by a state of the second CE signal received at the CE port.
8. The memory system of claim 5 , wherein the second CE signal is provided to the second CE port of the first memory chip and the CE port of the second memory chip via a common CE signal line.
9. The memory system of claim 5 , wherein the controller is further configured to provide third and fourth CE signals to a second multi-chip package (MCP) semiconductor memory device, wherein the second MCP semiconductor memory device comprises:
a third memory chip comprising a first CE port configured to receive the third CE signal, a second CE port configured to receive the fourth CE signal and an active termination unit, wherein the third memory chip is activated/deactivated in response to the third CE signal and configured to provide data to the data input/output (I/O) bus via the active termination unit; and
a fourth memory chip comprising a CE port configured to receive the fourth CE signal, wherein the fourth memory chip is activated/deactivated in response to the fourth CE signal and configured to provide data to the data input/output (I/O) bus,
wherein the active termination unit is turned ON only when both of the third and fourth memory chips are deactivated.
10. A method of operating multi-chip package (MCP) semiconductor memory device including first and second memory chips sharing a common data input/output (I/O) bus, the method comprising:
receiving first and second chip enable (CE) signals at the first memory chip;
determining whether the first memory chip is activated based on the first CE signal;
determining whether the second memory chip is activated based on the second CE signal; and
turning ON an active termination unit of the first memory chip, connecting the first memory chip to the data I/O bus, only when both of the first and second memory chips are deactivated.
11. The method of claim 10 , wherein the second CE signal is provided to the first and second memory chips via a common CE signal line.
12. The method of claim 10 , wherein the first and second CE signals are provided from a controller configured to control the operation of the first and second memory chips.
13. The method of claim 10 , wherein the MCP semiconductor memory device comprise N memory chips sharing the data I/O bus, wherein the first memory chip within the N memory chips is one of the first through N−1 th memory chips and the second memory chip is the N th memory chip.
14. The semiconductor memory device of claim 1 , wherein the active termination unit of the first memory chip is the only active termination unit used by the semiconductor memory device for terminating the data input/output (I/O) bus.
15. The semiconductor memory device of claim 9 , wherein the active termination unit of the first memory chip is the only active termination unit used by the first MCP semiconductor memory device for terminating the data input/output (I/O) bus, and the active termination unit of the third memory chip is the only active termination unit used by the second MCP semiconductor memory device for terminating the data input/output (I/O) bus.