NT5SV64M4AT Datasheet, PDF (3/65 Pages) List of Unclassifed Manufacturers – 256Mb Synchronous DRAM

NT5SV64M4AT(L)
NT5SV32M8AT(L)
NT5SV16M16AT(L)
256Mb Synchronous DRAM
Pin Description
CK
CKE (CKE0, CKE1)
CS
RAS
CAS
WE
BA1, BA0
A0 - A12
Clock Input
Clock Enable
Chip Select
Row Address Strobe
Column Address Strobe
Write Enable
Bank Select
Address Inputs
DQ0-DQ15
DQM, LDQM, UDQM
V_DD
V_SS
V_DDQ
V_SSQ
NC
—
Data Input/Output
Data Mask
Power (+3.3V)
Ground
Power for DQs (+3.3V)
Ground for DQs
No Connection
—
Input/Output Functional Description
Symbol
Type
Polarity
Function
CK
Input
Positive
Edge
The system clock input. All of the SDRAM inputs are sampled on the rising edge of the clock.
CKE, CKE0,
CKE1
Input
Active High
Activates the CK signal when high and deactivates the CK signal when low. By deactivating the
clock, CKE low initiates the Power Down mode, Suspend mode, or the Self Refresh mode.
CS
Input
Active Low
CS enables the command decoder when low and disables the command decoder when high. When
the command decoder is disabled, new commands are ignored but previous operations continue.
RAS, CAS, WE
Input
Active Low
When sampled at the positive rising edge of the clock, CAS, RAS, and WE define the operation to be
executed by the SDRAM.
BA1, BA0
Input
—
Selects which bank is to be active.
A0 - A12
Input
During a Bank Activate command cycle, A0-A12 defines the row address (RA0-RA12) when sam-
pled at the rising clock edge.
During a Read or Write command cycle, A0-A9 and A11 defines the column address (CA0-CA9,
CA11), when sampled at the rising clock edge. Assume the x4 organization.
—
A10 is used to invoke auto-precharge operation at the end of the burst read or write cycle. If A10 is
high, auto-precharge is selected and BA0, BA1 defines the bank to be precharged. If A10 is low,
autoprecharge is disabled.
During a Precharge command cycle, A10 is used in conjunction with BA0, BA1 to control which
bank(s) to precharge. If A10 is high, all banks will be precharged regardless of the state of BS. If A10
is low, then BA0 and BA1 are used to define which bank to precharge.
DQ0 - DQ15
Input-
Output
—
Data Input/Output pins operate in the same manner as on conventional DRAMs.
DQM
LDQM
UDQM
Input
The Data Input/Output mask places the DQ buffers in a high impedance state when sampled high. In
x16 products, the LDQM and UDQM control the lower and upper byte I/O buffers, respectively. In
Active High
Read mode, DQM has a latency of two clock cycles and controls the output buffers like an output
enable. DQM low turns the output buffers on and DQM high turns them off. In Write mode, DQM has
a latency of zero and operates as a word mask by allowing input data to be written if it is low but
blocks the write operation if DQM is high.
V_DD , V_SS
Supply
—
V_DDQ V_SSQ
Supply
—
Power and ground for the input buffers and the core logic.
Isolated power supply and ground for the output buffers to provide improved noise immunity.
REV 1.0
May, 2001
3
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