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November 2, 2004 pSRAM_Type07_13_A1
pSRAM Type 7
135
A d v a n c e i n f o r m a t i o n
Functional Description
Legend:
L = V
IL
, H = V
IH
, X can be either V
IL
or V
IH
, High-Z = High Impedance.
Notes:
1. Should not be kept this logic condition longer than 1 ms. Please contact local Spansion representative for the relaxation of
1ms limitation.
2. Power Down mode can be entered from Standby state and all DQ pins are in High-Z state. Data retention depends on the
selection of the Power-Down Program, 16M has data retention in all modes except Power Down. Refer to Power Down for
details.
3. Can be either V
IL
or V
IH
but must be valid before Read or Write.
Power Down (for 32M, 64M Only)
Power Down
The Power Down is a low-power idle state controlled by CE2. CE2 Low drives the
device in power-down mode and maintains the low-power idle state as long as
CE2 is kept Low. CE2 High resumes the device from power-down mode. These
devices have three power-down modes. These can be programmed by series of
read/write operation. Each mode has following features.
The default state is Sleep and it is the lowest power consumption but all data is
lost once CE2 is brought to Low for Power Down. It is not required to program to
Sleep mode after power-up.
Mode
CE2#
CE1#
WE#
OE#
LB#
UB#
A
21-0
DQ
8-1
DQ
16-9
Standby (Deselect)
H
H
X
X
X
X
X
High-Z
High-Z
Output Disable (Note 1)
H
L
H
H
X
X
Note 3
High-Z
High-Z
Output Disable (No Read)
H
L
H
H
Valid
High-Z
High-Z
Read (Upper Byte)
H
L
Valid
High-Z
Output Valid
Read (Lower Byte)
L
H
Valid
Output Valid
High-Z
Read (Word)
L
L
Valid
Output Valid
Output Valid
No Write
L
H
H
H
Valid
Invalid
Invalid
Write (Upper Byte)
H
L
Valid
Invalid
Input Valid
Write (Lower Byte)
L
H
Valid
Input Valid
Invalid
Write (Word)
L
L
Valid
Input Valid
Input Valid
Power Down
L
X
X
X
X
X
X
High-Z
High-Z
32M
64M
Mode
Retention Data
Retention Address
Mode
Retention Data
Retention Address
Sleep (default)
No
N/A
Sleep (default)
No
N/A
4M Partial
4M bit
00000h to 3FFFFh
8M Partial
8M bit
00000h to 7FFFFh
8M Partial
8M bit
00000h to 7FFFFh
16M Partial
16M bit
00000h to FFFFFh