Rev. 1.0 December 2007
K4T2G044QA
2Gb DDR2 SDRAM
K4T2G084QA
8 of 43
Symbol Type Function
CK, CK
Input
Clock: CK and CK
are differential clock inputs. All address and control input signals are sampled on the crossing of
the positive edge of CK and negative edge of CK
. Output (read) data is referenced to the crossings of CK and CK
(both directions of crossing).
CKE Input
Clock Enable: CKE HIGH activates, and CKE Low deactivates, internal clock signals and device input buffers and
output drivers. Taking CKE Low provides Precharge Power-Down and Self Refresh operation (all banks idle), or
Active Power-Down (row Active in any bank). CKE is synchronous for power down entry and exit, and for self
refresh entry. CKE is asynchronous for self refresh exit. After V
REF
has become stable during the power on and ini-
tialization swquence, it must be maintained for proper operation of the CKE receiver. For proper self-refresh entry
and exit, V
REF
must be maintained to this input. CKE must be maintained high throughout read and write accesses.
Input buffers, excluding CK, CK
, ODT and CKE are disabled during power-down. Input buffers, excluding CKE, are
disabled during self refresh.
CS Input
Chip Select: All commands are masked when CS
is registered HIGH. CS provides for external Rank selection on
systems with multiple Ranks. CS
is considered part of the command code.
ODT Input
On Die Termination: ODT (registered HIGH) enables termination resistance internal to the DDR2 SDRAM. When
enabled, ODT is only applied to each DQ, DQS, DQS
, RDQS, RDQS, and DM signal for x4/x8 configurations. For
x16 configuration, ODT is applied to each DQ, UDQS/UDQS
, LDQS/LDQS, UDM, and LDM signal. The ODT pin
will be ignored if the Extended Mode Register Set(EMRS) is programmed to disable ODT.
RAS
, CAS, WE Input Command Inputs: RAS, CAS and WE (along with CS) define the command being entered.
DM
(UDM), (LDM)
Input
Input Data Mask: DM is an input mask signal for write data. Input data is masked when DM is sampled HIGH coin-
cident with that input data during a Write access. DM is sampled on both edges of DQS. Although DM pins are input
only, the DM loading matches the DQ and DQS loading. For x8 device, the function of DM or RDQS/RDQS
is
enabled by EMRS command.
BA0 - BA2 Input
Bank Address Inputs: BA0, BA1 and BA2 define to which bank an Active, Read, Write or Precharge command is
being applied. Bank address also determines if the mode register or extended mode register is to be accessed dur-
ing a MRS or EMRS cycle.
A0 - A14 Input
Address Inputs: Provided the row address for Active commands and the column address and Auto Precharge bit
for Read/Write commands to select one location out of the memory array in the respective bank. A10 is sampled
during a Precharge command to determine whether the Precharge applies to one bank (A10 LOW) or all banks
(A10 HIGH). If only one bank is to be precharged, the bank is selected by BA0, BA1 and BA2. The address inputs
also provide the op-code during Mode Register Set commands.
DQ Input/Output Data Input/ Output: Bi-directional data bus.
DQS, (DQS
)
(LDQS), (LDQS
)
(UDQS), (UDQS
)
(RDQS), (RDQS
)
Input/Output
Data Strobe: Output with read data, input with write data. Edge-aligned with read data, centered in write data. For
the x16, LDQS corresponds to the data on DQ0-DQ7; UDQS corresponds to the data on DQ8-DQ15. For the x8, an
RDQS option using DM pin can be enabled via the EMRS(1) to simplify read timing. The data strobes DQS, LDQS,
UDQS, and RDQS may be used in single ended mode or paired with optional complementary signals DQS
, LDQS,
UDQS
, and RDQS to provide differential pair signaling to the system during both reads and writes. A control bit at
EMRS(1)[A10] enables or disables all complementary data strobe signals.
In this data sheet, "differential DQS signals" refers to any of the following with A10 = 0 of EMRS(1)
x4 DQS/DQS
x8 DQS/DQS if EMRS(1)[A11] = 0
x8 DQS/DQS
, RDQS/RDQS, if EMRS(1)[A11] = 1
x16 LDQS/LDQS
and UDQS/UDQS
"single-ended DQS signals" refers to any of the following with A10 = 1 of EMRS(1)
x4 DQS
x8 DQS if EMRS(1) [A11] = 0
x8 DQS, RDQS, if EMRS(1) [A11] = 1
x16 LDQS and UDQS
NC No Connect: No internal electrical connection is present.
V
DD
/V
DDQ
Supply
Power Supply: 1.8V +/- 0.1V, DQ Power Supply: 1.8V +/- 0.1V
V
SS
/V
SSQ
Supply
Ground, DQ Ground
V
DDL
Supply
DLL Power Supply: 1.8V +/- 0.1V
V
SSDL
Supply
DLL Ground
V
REF
Supply
Reference voltage
4.0 Input/Output Functional Description
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