UL634H256
Not Recommended For New Designs
Features
High-performance CMOS non-
volatile static RAM 32768 x 8 bits
35 and 45 ns Access Times
15 and 20 ns Output Enable
Access Times
I
CC
= 8 mA typ. at 200 ns Cycle
Time
Automatic STORE to EEPROM
on Power Down using external
capacitor
Software initiated STORE
Automatic STORE Timing
10
6
STORE cycles to EEPROM
100 years data retention in
EEPROM
Automatic RECALL on Power Up
Software RECALL Initiation
Unlimited RECALL cycles from
EEPROM
Wide voltage range: 2.7 ... 3.6 V
(3.0 ... 3.6 V for 35 ns type)
Operating temperature range:
0 to 70 °C
-40 to 85 °C
-40 to 125 °C
QS 9000 Quality Standard
ESD protection > 2000 V
(MIL STD 883C M3015.7-HBM)
RoHS compliance and Pb- free
Package:SOP 32 (300 mil)
Low Voltage
PowerStore
32K x 8 nvSRAM
Description
The UL634H256 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 UL634H256 is a fast static
RAM (35 and 45 ns), with a nonvo-
latile electrically erasable PROM
(EEPROM) element incorporated
in each static memory cell. The
SRAM can be read and written an
unlimited number of times, while
independent nonvolatile data resi-
des in EEPROM.
Data transfers from the SRAM to
the EEPROM (the STORE opera-
tion) take place automatically upon
power down using charge stored in
an external 68
μF
capacitor. Trans-
fers from the EEPROM to the
SRAM (the RECALL operation)
take place automatically on power
up.
The UL634H256 combines the
high performance and ease of use
of a fast SRAM with nonvolatile
data integrity.
STORE cycles also may be initia-
ted under user control via a soft-
ware sequence or via a single pin
(HSB).
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.
RECALL cycles may also be initia-
ted by a software sequence.
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.
Pin Configuration
Pin Description
Signal Name
VCAP
A14
A12
A7
A6
A5
A4
A3
n.c.
A2
A1
A0
DQ0
DQ1
DQ2
VSS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
VCCX
HSB
W
A13
A8
A9
A11
G
n.c.
A10
E
DQ7
DQ6
DQ5
DQ4
DQ3
Signal Description
Address Inputs
Data In/Out
Chip Enable
Output Enable
Write Enable
Power Supply Voltage
Ground
Capacitor
Hardware Controlled Store/Busy
A0 - A14
DQ0 - DQ7
E
G
W
VCCX
VSS
VCAP
HSB
SOP
Top View
August 15, 2006
STK Control #ML0058
1
Rev 1.1
SIMTEK [ SIMTEK CORPORATION ]
