128M DDR SDRAM
K4D263238D
-5- Rev. 1.3 (Jul. 2002)
INPUT/OUTPUT FUNCTIONAL DESCRIPTION
*1 : The timing reference point for the differential clocking is the cross point of CK and CK.
For any applications using the single ended clocking, apply VREF to CK pin.
Symbol Type Function
CK, CK*1 Input
The differential system clock Input.
All of the inputs are sampled on the rising edge of the clock except
DQ′sandDM′s that are sampled on both edges of the DQS.
CKE Input
Activates the CK signal when high and deactivates the CK signal
when low. By deactivating the clock, CKE low indicates the Power
down mode or Self refresh mode.
CS Input
CS enables the command decoder when low and disabled the com-
mand decoder when high. When the command decoder is disabled,
new commands are ignored but previous operations continue.
RAS Input Latches row addresses on the positive going edge of the CK with
RAS low. Enables row access & precharge.
CAS Input Latches column addresses on the positive going edge of the CK with
CAS low. Enables column access.
WE Input Enables write operation and row precharge.
Latches data in starting from CAS,WEactive.
DQS Input/Output Data input and output are synchronized with both edge of DQS.
DM0~DM3Input
Data In mask. Data In is masked by DM Latency=0 when DM is high
in burst write. DM0for DQ0~DQ7, DM1for DQ8~DQ15, DM2for
DQ16 ~DQ23, DM3for DQ24 ~DQ31.
DQ0~DQ31 Input/Output Data inputs/Outputs are multiplexed on the same pins.
BA0,BA1Input Selects which bank is to be active.
A0~A11 Input
Row/Column addresses are multiplexed on the same pins.
Row addresses : RA0~RA11, Column addresses : CA0~CA7.
Column address CA8is used for auto precharge.
VDD/VSS Power Supply Power and ground for the input buffers and core logic.
VDDQ/VSSQ Power Supply Isolated power supply and ground for the output buffers to provide
improved noise immunity.
VREF Power Supply Reference voltage for inputs, used for SSTL interface.
MCL Must Connect Low Must connect Low