64Mb: x32
SDRAM
PIN DESCRIPTIONS
PIN NUMBERS
68
SYMBOL
CLK
TYPE
Input
DESCRIPTION
Clock: CLK is driven by the system clock. All SDRAM input signals are
sampled on the positive edge of CLK. CLK also increments the internal burst
counter and controls the output registers.
Clock Enable: CKE activates (HIGH) and deactivates (LOW) the CLK signal.
Deactivating the clock provides PRECHARGE POWER-DOWN and SELF REFRESH
operation (all banks idle), ACTIVE POWER-DOWN (row active in any bank) 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 CLK, are disabled during power-down and self refresh
modes, providing low standby power. CKE may be tied HIGH.
Chip Select: CS# enables (registered LOW) and disables (registered HIGH) the
command decoder. All commands are masked when CS# is registered HIGH.
CS# provides for external bank selection on systems with multiple banks.
CS# is considered part of the command code.
Command Inputs: WE# , CAS#, and RAS# (along with CS#) define the
command being entered.
Input/Output Mask: DQM is sampled HIGH and is an input mask signal
for write accesses and an output enable signal for read accesses. Input data
is masked during a WRITE cycle. The output buffers are placed in a High-Z
state (two-clock latency) during a READ cycle. DQM0 corresponds to DQ0-
DQ7; DQM1 corresponds to DQ8-DQ15; DQM2 corresponds to DQ16-DQ23;
and DQM3 corresponds to DQ24-DQ31. DQM0-DQM3 are considered same
state when referenced as DQM.
Bank Address Input(s): BA0 and BA1 define to which bank the ACTIVE, READ,
WRITE or PRECHARGE command is being applied.
Address Inputs: A0-A10 are sampled during the ACTIVE command (row-
address A0-A10) and READ/WRITE command (column-address A0-A7 with A10
defining auto precharge) to select one location out of the memory array in
the respective bank. A10 is sampled during a PRECHARGE command to
determine if all banks are to be precharged (A10 HIGH) or bank selected by
BA0, BA1 (LOW). The address inputs also provide the op-code during a LOAD
MODE REGISTER command.
67
CKE
Input
20
CS#
Input
17, 18, 19
16, 71, 28, 59
WE#, CAS#,
RAS#
DQM0-
DQM3
Input
Input
22, 23
25-27, 60-66, 24
BA0, BA1
A0-A10
Input
Input
2, 4, 5, 7, 8, 10, 11, 13,
74, 76, 77, 79, 80, 82, 83,
85, 31, 33, 34, 36, 37, 39,
40, 42, 45, 47, 48, 50, 51,
53, 54, 56
14, 21, 30, 57, 69, 70, 73
3, 9, 35, 41, 49, 55, 75, 81
6, 12, 32, 38, 46, 52, 78, 84
1, 15, 29, 43
44, 58, 72, 86
DQ0-DQ31
Input/ Data I/Os: Data bus.
Output
NC
V
DD
Q
V
SS
Q
V
DD
V
SS
–
Supply
Supply
Supply
Supply
No Connect: These pins should be left unconnected. Pin 70 is reserved
for SSTL reference voltage supply.
DQ Power Supply: Isolated on the die for improved noise immunity.
DQ Ground: Provide isolated ground to DQs for improved noise immunity.
Power Supply: +3.3V ±0.3V. (See note 27 on page 35.)
Ground.
64Mb: x32 SDRAM
64MSDRAMx32_5.p65 – Rev. B; Pub. 6/02
5
Micron Technology, Inc., reserves the right to change products or specifications without notice.
©2002, Micron Technology, Inc.
MICRON [ MICRON TECHNOLOGY ]
