is42s16160a1-7t Integrated Silicon Solution, Inc., is42s16160a1-7t Datasheet - Page 15

• Manufacturer Part Number: is42s16160a1-7t
• Description: 256 Mb Synchronous Dram
• Manufacturer: Integrated Silicon Solution, Inc.

IS42S83200A1
IS42S16160A1
Integrated Silicon Solution, Inc. — 1-800-379-4774
Rev. B
10/28/05
A0-9,11-12
OPERATIONAL DESCRIPTION
BANK ACTIVATE
The SDRAM has four independent banks. Each bank
is activated by the ACT command with the bank ad-
dresses (BA0,1). A row is indicated by the row ad-
dresses A0-12. The minimum activation interval be-
tween one bank and the other bank is tRRD.Multiple
banks can be active state concurrently by issuing mul­
tiple ACT commands.
PRECHARGE
The PRE command deactivates the bank indicated
by BA0,1. When multiple banks are active, the
precharge all command (PREA, PRE + A10=H) is
available to deactivate them at the same time.
After tRP from the precharge, an ACT command to the
same bank can be issued.BA0-1 are “DON’T CARE”
in this case.
Command
BA0-1
CLK
A10
DQ
ACT
Xa
Xa
00
(4-bank x 8,388,608 - word x 8-bit)
(4-bank x 4,194,304 - word x 16-bit)
tRRD
Bank Activation and Precharge All (BL=4, CL=3)
ACT
Xb
Xb
01
tRCD
READ
Yb
01
0
Qb0
READ
After tRCD from the bank activation, a READ
command can be issued. 1st output data is avail-
able after the /CAS Latency from the READ, fol­
lowed by (BL -1) consecutive data when the Burst
Length is BL. The start address is specified by
A0-9(X8), A0-8(X16) , and the address sequence of
burst data is defined by the Burst Type.
A READ command may be applied to any
active bank, so the row precharge time (tRP) can be
hidden behind continuous output data by
interleaving the multiple banks. When A10 is high
a t a R E A D c o m m a n d , t h e a u t o - p r e c h a r g e
(READA) is performed. Any command (READ,
WRITE, PRE, TBST, ACT) to the same bank is
inhibited till the internal precharge is complete.
The internal precharge starts at BL after READA.
The next ACT command can be issued after (BL
+ tRP) from the previous READA.
In any case, tRCD+BL
Qb1
Precharge All
PRE
Qb2
1
Qb3
tRP
tRASmin must be met.
ACT
Xa
Xa
00
ISSI
15
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