256MB / 512MB (x64)
168-PIN SDRAM DIMMs
Table 6:
Pin Descriptions
SYMBOL
RAS#, CAS#,
WE#
CK0-CK3
TYPE
Input
Input
DESCRIPTION
Command Inputs: RAS#, CAS#, and WE# (along with S#)
define the command being entered.
Clock: CK is driven by the system clock. All SDRAM input
signals are sampled on the positive edge of CK. CK also
increments the internal burst counter and controls the output
registers.
Clock Enable: CKE activates (HIGH) and deactivates (LOW) the
CK signal. Deactivating the clock provides PRECHARGE
POWER-DOWN and SELF REFRESH operation (all device banks
idle) or CLOCK SUSPEND OPERATION (burst access in
progress). CKE is synchronous except after the device enters
power- down and self refresh modes, where CKE becomes
asynchronous until after exiting the same mode. The input
buffers, including CK, are disabled during power-down and
self refresh modes, providing low standby power.
Chip Select: S# enables (registered LOW) and disables
(registered HIGH) the command decoder. All commands are
masked when S# is registered HIGH. S# is considered part of
the command code.
Input/Output Mask: DQMB is an input mask signal for write
accesses and an output enable signal for read accesses. Input
data is masked when DQMB is sampled HIGH during a WRITE
cycle. The output buffers are placed in a High-Z state (two-
clock latency) when DQMB is sampled HIGH during a READ
cycle.
Bank Address: BA0 and BA1 define to which device bank the
ACTIVE, READ, WRITE, or PRECHARGE command is being
applied.
Address Inputs: Provide the row address for ACTIVE
commands, and the column address and auto prcharge bit
(A10) for READ/WRITE commands, to select one location out
of the memory arrary in the respective device bank. A10
sampled during a PRECHARGE command determines whether
the PRECHARGE applies to one device bank (A10 LOW, device
bank selected by BA0, BA1) or all device banks (A10 HIGH).
The address inputs also provide the op-code during a MODE
REGISTER SET command.
Serial Clock for Presence-Detect: SCL is used to synchronize
the presence-detect data transfer to and from the module.
Presence-Detect Address Inputs: These pins are used to
configure the presence-detect device.
Data I/O: Data bus.
Pin numbers may not correlate with symbols. Refer to the Pin Assignment table for pin number and symbol information.
PIN NUMBERS
27, 111, 115
42, 79, 125, 163
63, 128
CKE0, CKE1
Input
30, 45,114, 129
S0# -S3#
Input
28, 29, 46, 47, 112, 113, 130,
131
DQMB0-DQMB7
Input
39, 122
BA0, BA1
Input
33 - 38, 117 - 121, 123, 126
A0-A12
Input
83
165-167
2-5, 7-11, 13-17, 19-20, 55-58,
60, 65-67, 69-72, 74-77, 86-89,
91-95, 97-101, 103-104,
139-142, 144, 149-151,
153-156,158-161
82
SCL
SA0-SA2
DQ0-DQ63
Input
Input
Input/
Output
SDA
Input/ Serial Presence-Detect Data: SDA is a bidirectional pin used to
Output transfer addresses and data into and out of the presence-
detect portion of the module.
32,64 Meg x 64 SDRAM DIMMs
SD8_16C32_64x64AG_C.fm - Rev. C 11/02
3
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2002, Micron Technology Inc.
MICRON [ MICRON TECHNOLOGY ]
