W3H264M16E-XB2X
PRELIMINARY
TABLE 1 – BALL DESCRIPTIONS
Symbol
ODT0-1
CK, CK#
Type
Input
Input
Description
On-Die termination: ODT (registered HIGH) enables termination resistance internal to the DDR2 SDRAM. When enabled, ODT is only
applied to each of the following balls: DQ0–DQ15, LDM, UDM, LDQS, LDQS#, UDQS, and UDQS#. The ODT input will be ignored if
disabled via the LOAD MODE command.
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 data (DQS and DQS/DQS#) is referenced to the crossings of CK and CK#.
Clock enable: CKE (registered HIGH) activates and CKE (registered LOW) deactivates clocking circuitry on the DDR2 SDRAM. The
specific circuitry that is enabled/disabled is dependent on the DDR2 SDRAM configuration and operating mode. CKE LOW provides
PRECHARGE power-down mode and SELF-REFRESH action (all banks idle), or ACTIVE power-down (row active in any bank). CKE
is synchronous for power-down entry, Power-down exit, output disable, and for self refresh entry. CKE is asynchronous for self refresh
exit. Input buffers (excluding CKE, and ODT) are disabled during power-down. Input buffers (excluding CKE) are disabled during
self refresh. CKE is an SSTL_18 input but will detect a LVCMO SLOW level once VCC is applied during first power-up. After VREF has
become stable during the power on and initialization sequence, it must be maintained for proper operation of the CKE receiver. For
proper SELF-REFRESH operation, VREF must be maintained.
CKE0-1
Input
Chip select: CS# enables (registered LOW) and disables (registered HIGH) the command decoder. All commands are masked when
CS# is registered HIGH.
CS0-1#
Input
Input
RAS#, CAS#, WE#
Command inputs: RAS#, CAS#, WE# (along with CS#) define the command being entered.
Input data mask: DM is an input mask signal for write data. Input data is masked when DM is concurrently sampled HIGH during a
WRITE access. DM is sampled on both edges of DQS. Although DM balls are input-only, the DM loading is designed to match that of
DQ and DQS balls. LDM is DM for lower byte DQ0–DQ7 and UDM is DM for upper byte DQ8–DQ15.
LDM, UDM
BA0–BA2
Input
Input
Bank address inputs: BA0–BA2 define to which bank an ACTIVATE, READ, WRITE, or PRECHARGE command is being applied.
BA0–BA2 define which mode register including MR, EMR, EMR(2), and EMR(3) is loaded during the LOAD MODE command.
Address inputs: Provide the row address for ACTIVATE commands, and the column address and auto precharge bit (A10) for READ/
WRITE commands, to select one location out of the memory array in the respective bank. A10 sampled during a PRECHARGE
command determines whether the PRECHARGE applies to one bank (A10 LOW, bank selected by BA2–BA0) or all banks (A10
HIGH) The address inputs also provide the op-code during a LOAD MODE command.
A0-A12
Input
DQ0-15
I/O
I/O
Data input/output: Bidirectional data bus
Data strobe for upper byte: Output with read data, input with write data for source synchronous operation. Edge-aligned with read
data, center-aligned with write data. UDQS# is only used when differential data strobe mode is enabled via the LOAD MODE
command.
UDQS, UDQS#
Data strobe for lower byte: Output with read data, input with write data for source synchronous operation. Edge-aligned with read
data, center-aligned with write data. UDQS# is only used when differential data strobe mode is enabled via the LOAD MODE
command.
LDQS, LDQS#
I/O
VCC
VCCQ
VREF
VSS
Supply
Supply
Supply
Supply
-
Core Power Supply
I/Os Power Supply
SSTL_18 reference voltage.
Ground
DNU
Future use; Row address bit A13
Microsemi Corporation reserves the right to change products or specifications without notice.
March 2016 © 2016 Microsemi Corporation. All rights reserved.
Rev. 1
4
Microsemi Corporation • (602) 437-1520 • www.microsemi.com/pmgp
MERCURY [ MERCURY UNITED ELECTRONICS INC ]
