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U631H256 Datasheet, PDF (1/13 Pages) List of Unclassifed Manufacturers – SoftStore 32K x 8 nvSRAM
U631H256
SoftStore 32K x 8 nvSRAM
Features
Description
‡ High-performance CMOS non-
volatile static RAM 32768 x 8 bits
‡ 25 ns Access Times
‡ 10 ns Output Enable Access
Times
‡ Software STORE Initiation
‡ Automatic STORE Timing
‡ 106 STORE cycles to EEPROM
‡ 100 years data retention in
EEPROM
‡ Automatic RECALL on Power Up
‡ Software RECALL Initiation
‡ Unlimited RECALL cycles from
EEPROM
‡ Unlimited Read and Write to
SRAM
‡ Single 5 V ± 10 % Operation
‡ Operating temperature ranges:
0 to 70 °C
-40 to 85 °C
‡ QS 9000 Quality Standard
‡ ESD protection > 2000 V
(MIL STD 883C M3015.7-HBM)
‡ RoHS compliance and Pb- free
Package: SOP28 (330 mil)
The U631H256 has two separate
modes of operation: SRAM mode
and nonvolatile mode. In SRAM
mode, the memory operates as an
ordinary static RAM. In nonvolatile
operation, data is transferred in
parallel from SRAM to EEPROM or
from EEPROM to SRAM. In this
mode SRAM functions are disab-
led.
The U631H256 is a fast static RAM
(25 ns), with a nonvolatile electri-
cally erasable PROM (EEPROM)
element incorporated in each static
memory cell. The SRAM can be
read and written an unlimited num-
ber of times, while independent
nonvolatile data resides in
EEPROM. Data transfers from the
SRAM to the EEPROM (the
STORE operation), or from the
EEPROM to the SRAM (the
RECALL operation) are initiated
through software sequences.
The U631H256 combines the high
performance and ease of use of a
fast SRAM with nonvolatile data
integrity.
Once a STORE cycle is initiated,
further input or output are disabled
until the cycle is completed.
Because a sequence of addresses
is used for STORE initiation, it is
important that no other read or
write accesses intervene in the
sequence or the sequence will be
aborted.
Internally, RECALL is a two step
procedure. First, the SRAM data is
cleared and second, the nonvola-
tile information is transferred into
the SRAM cells.
The RECALL operation in no way
alters the data in the EEPROM
cells. The nonvolatile data can be
recalled an unlimited number of
times.
The U631H256 is pin compatible
with standard SRAMs.
Pin Configuration
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
VSS
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8 SOP 21
9
20
10
19
11
18
12
17
13
16
14
15
VCC
W
A13
A8
A9
A11
G
A10
E
DQ7
DQ6
DQ5
DQ4
DQ3
Top View
March 31, 2006
STK Control #ML0043
Pin Description
Signal Name
A0 - A14
DQ0 - DQ7
E
G
W
VCC
VSS
Signal Description
Address Inputs
Data In/Out
Chip Enable
Output Enable
Write Enable
Power Supply Voltage
Ground
1
Rev 1.0