Data Sheet
64Mbit – High Speed SDRAM
8Mx8, 4Mx16 HSDRAM
Pin Descriptions
Symbol
CLK
CKE
Type
Input
Input
Function
Clocks: All SDRAM input signals are sampled on the positive edge of CLK.
Clock Enable: CKE activate (high) or deactivate (low) the CLK signals. Deactivating the
clock initiates the Power-Down and Self-Refresh operations (all banks idle), or Clock
Suspend operation. CKE is synchronous until the device enters Power-Down and Self-
Refresh modes where it is asynchronous until the mode is exited.
Chip Select: CS# enables (low) or disables (high) the command decoder. When the
command decoder is disabled, new commands are ignored but previous operations
continue.
Command Inputs: Sampled on the rising edge of CLK, these inputs define the command
to be executed.
Bank Addresses: These inputs define to which of the 4 banks a given command is being
applied.
Address Inputs: A0-A11 define the row address during the Bank Activate command. A0-
A8 define the column address during Read and Write commands. A10/AP invokes the
Auto-precharge operation. During manual Precharge commands, A10/AP low specifies a
single bank precharge while A10/AP high precharges all banks. The address inputs are
also used to program the Mode Register.
Data I/O: Data bus inputs and outputs. For Write cycles, input data is applied to these
pins and must be set-up and held relative to the rising edge of clock. For Read cycles, the
device drives output data on these pins after the CAS latency is satisfied.
Data I/O Mask Inputs: DQM inputs mask write data (zero latency) and acts as a
synchronous output enable (2-cycle latency) for read data.
Power Supply: +3.3 V
Ground
No connect - open pin.
CS#
Input
RAS#, CAS#,
WE#
BA1, BA0
A0-A11
Input
Input
Input
DQ0-DQ15
Input/
Output
DQM,
UDQM,
LDQM
V
DD
V
SS
NC
Input
Supply
Supply
-
Enhanced Memory Systems Inc., 1850 Ramtron Dr., Colo Spgs, CO 80921
PHONE: (800) 545-DRAM; FAX: (719) 488-9095;
http://www.edram.com
1999 Enhanced Memory Systems. All rights reserved.
The information contained herein is subject to change without notice.
Revision 1.1
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RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
