EM44CM1688LBA
Pin Description (Simplified)
Pin
Name
Function
(System Clock)
J8,K8
CK,/CK
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).
(Chip Select)
L8
/CS
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.
(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. 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.
(Address)
M8,M3,M7,N2,
N8,N3,N7,P2,
P8,P3,M2,P7,
R2
A0~A12
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.
The address inputs also provide the op-code during Mode Register Set
commands.
(Bank Address)
L2,L3
BA0, BA1
BA0 - BA1 define to which bank an Active, Read, Write or Precharge
command is being applied (For 256Mb and 512Mb, BA2 is not applied).
Bank address also determines if the mode register or extended mode
register is to be accessed during a MRS or EMRS cycle.
(On Die Termination)
K9
ODT
ODT (registered HIGH) enables termination resistance internal to the
DDR2 SDRAM. When enabled, 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 (EMRS(1)) is programmed to
disable ODT.
(Command Inputs)
/RAS, /CAS and /WE (along with /CS) define the command being
entered.
K2
CKE
K7, L7, K3
/RAS, /CAS,
/WE
Jun. 2010
5/28
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