Rev. 0.3 / Feb. 2005

9

4Banks x 2M x 16bits Synchronous DRAM

Precharge

The Precharge command is used to close the open row in a particular bank or the open row in all banks. When the

precharge command is issued with address A10, high, then all banks will be precharged, and If A10 is low, the open

row in a particular bank will be precharged. The bank(s) will be available when the minimum tRP time is met after the

precharge command is issued.

Auto Precharge

The Auto Precharge command is issued to close the open row in a particular bank after READ or WRITE operation. If

A10 is high when a READ or WRITE command is issued, the READ or WRITE with Auto Precharge is initiated.

Burst Termination

The Burst Termination is used to terminate the burst operation. This function can be accomplished by asserting a Burst

Stop command or a Precharge command during a burst READ or WRITE operation. The Precharge command interrupts

a burst cycle and close the active bank, and the Burst Stop command terminates the existing burst operation leave the

bank open.

Data Mask

The Data Mask comamnd is used to mask READ or WRITE data. During a READ operation, When this command is

issued, data ouputs are disabled and become high impedance after two clock delay. During a WRITE operation, When

this command is issued, data inputs can't be written with no clock delay.

Clock Suspend

The Clock Suspend command is used to suspend the internal clock of DRAM. During normal access mode, CKE is keeping

High. When CKE is low, it freezes the internal clock and extends data Read and Write operations.

Power Down

The Power Down command is used to reduce standby current. Before this command is issued, all banks must be pre-

charged and tRP must be passed after a precharge command. Once the Power Down command is initiated by keeping

CKE low, all of the input buffer except CKE are gated off.

Auto Refresh

This command must be issued each time a refresh is required. When an Auto Refresh command is issued , the address

bits is ''Don't care'', because the specific address bits is generated by internal refresh address counter.

Self Refresh

The Self Refresh command is used to retain cell data in the Mobile SDR. In the Self Refresh mode, the Mobile SDR

operates refresh cycle asynchronously.

The Self Refresh command is initiated like an Auto Refresh command except CKE is disabled(Low). The LP SDRAM can

accomplish an special Self Refresh operation by the specific modes(PASR) programmed in extended mode registers.

The LP SDRAM can control the refresh rate automatically by the temperature value of Auto TCSR(Temperature Com-

pensated Self Refresh) to reduce self refresh current and select the memory array to be refreshed by the value of

Deep Power Down

The Deep Power Down Mode is used to achieve maximum power reduction by cutting the power of the whole memory

array of the devices.

For more information, see the special operation for Low Power consumption of this data sheet.