IC42S16102 Datasheet, PDF (25/78 Pages) Integrated Circuit Solution Inc – 512K x 16 Bit x 2 Banks (16-MBIT) SDRAM

IC42S16102
Read With Auto-Precharge
The read with auto-precharge command first executes a
burst read operation and then puts the selected bank in the
precharged state automatically. After the precharge com-
pletes, the bank goes to the idle state. Thus this command
performs a read command and a precharge command in
a single operation.
During this operation, the delay period (tPQL) between the
last burst data output and the start of the precharge
operation differs depending on the CAS latency setting.
When the CAS latency setting is two, the precharge
operation starts on one clock cycle before the last burst
data is output (tPQL = –1). When the CAS latency setting is
three, the precharge operation starts on two clock cycles
before the last burst data is output (tPQL = –2). Therefore,
the selected bank can be made active after a delay of tRP
from the start position of this precharge operation.
The selected bank must be set to the active state before
executing this command.
The auto-precharge function is invalid if the burst length is
set to full page.
CAS Latency
tPQL
3
2
–2
–1
CLK
COMMAND READA 0
I/O
DOUT 0
DOUT 1
tPQL
DOUT 2 DOUT 3
ACT 0
READ WITH AUTO-PRECHARGE
PRECHARGE START
tRP
(BANK 0)
CAS latency = 2, burst length = 4
CLK
COMMAND READA 0
I/O
READ WITH AUTO-PRECHARGE
(BANK 0)
CAS latency = 3, burst length = 4
DOUT 0
DOUT 1
tPQL
DOUT 2
DOUT 3
PRECHARGE START
tRP
ACT 0
Integrated Circuit Solution Inc.
25
DR042-0A 01/18/2005