Features
p
High-performance CMOS nonvolatile static RAM 8192 x 8 bits
p
25, 35 and 45 ns Access Times
p
12, 20 and 25 ns Output Enable
Access Times
p
Software STORE Initiation
(STORE Cycle Time < 10 ms)
p
Automatic STORE Timing
p
105 STORE cycles to EEPROM
p
10 years data retention in
EEPROM
p
Automatic RECALL on Power Up
p
Software RECALL Initiation
(RECALL Cycle Time < 20 µs)
p
Unlimited RECALL cycles from
EEPROM
p
Unlimited Read and Write to
SRAM
p
Single 5 V ± 10 % Operation
p
Operating temperature ranges:
p
CECC 90000 Quality Standard
p
ESD characterization according
MIL STD 883C M3015.7-HBM
(classification see IC Code
Numbers)
0 to 70 °C
-40 to 85 °C
p
Packages:PDIP28 (300 mil)
SOP28 (330 mil)
Description
The U631H64 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 disabled.
The U631H64 is a fast static RAM
(25, 35, 45 ns), with a nonvolatile
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 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.
U631H64
SoftStore
The U631H64 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 nonvolatile
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.
8K x 8 nvSRAM
Pin Configuration Pin Description
PDIP
SOP
28
VCC
27
W
26
n.c.
25
A8
24
A9
23
A11
22
G
21
A10
20
E
19
DQ7
18
DQ6
17
DQ5
16
DQ4
15
DQ3
Signal Name Signal Description
A0 - A12 Address Inputs
DQ0 - DQ7 Data In/Out
E
G
W
VCC Power Supply Voltage
VSS Ground
1
1
n.c.
2
A12
3
A7
4
A6
5
A5
6
A4
7
A3
8
A2
9
A1
10
A0
11
DQ0
12
DQ1
13
DQ2
14
VSS
Top View
December 12, 1997
Chip Enable
Output Enable
Write Enable
U631H64
Block Diagram
A5
A6
A7
A8
A9
A11
A12
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
64 x 8 Columns
Row Decoder
Column Decoder
Input Buffers
A0 A1 A2 A3 A4A10
EEPROM Array
Array
128 Rows x
Column I/O
128 x (64 x 8)
STORE
RECALLSRAM
Store/
Recall
Control
Software
Detect
Truth Table for SRAM Operations
Operating Mode E W G DQ0 - DQ7
Standby/not selected H
**
Internal Read L H H High-Z
Read L H L Data Outputs Low-Z
Write L L
*
Data Inputs High-Z
*H or L
V
V
V
G
E
W
High-Z
CC
SS
CC
A0 - A12
Characteristics
All voltages are referenced to VSS = 0 V (ground).
All characteristics are valid in the power supply voltage range and in the operating temperature range specified.
Dynamic measurements are based on a rise and fall time of ≤ 5 ns, measured between 10 % and 90 % of V
input levels of V
with the exception of the t
Absolute Maximum Rating
Power Supply Voltage V
Input Voltage V
Output Voltage V
Power Dissipation P
Operating Temperature C-Type
Storage Temperature T
a:Stresses greater than those listed under „Absolute Maximum Ratings“ may cause permanent damage to the device. This is a stress
rating only, and functional operation of the device at condition above those indicated in the operational sections of this specification is
not implied. Exposure to absolute maximum rating conditions for extended periods may affect reliability.
= 0 V and VIH = 3 V. The timing reference level of all input and output signals is 1.5 V,
IL
-times and ten-times, in which cases transition is measured ± 200 mV from steady-state voltage.
dis
a
K-Type
Symbol Min. Max. Unit
CC
I
O
D
T
a
stg
-0.5 7 V
-0.3 VCC+0.5 V
-0.3 VCC+0.5 V
0
-40
-65 150 °C
2
,as well as
I
1W
70
85
°C
°C
December 12, 1997
U631H64
Recommended Operation
Conditions
Power Supply Voltage V
Input Low Voltage V
Input High Voltage V
Symbol Conditions Min. Max. Unit
CC
-2 V at Pulse Width
IL
10 ns permitted
IH
DC Characteristics Symbol Conditions
Operating Supply Current
Average Supply Current during
c
STORE
Standby Supply Current
(Cycling TTL Input Levels)
b
d
I
V
CC1
V
V
t
t
t
V
I
CC2
E
W
V
V
I
CC(SB)1VCC
E
= 5.5 V
CC
= 0.8 V
IL
= 2.2 V
IH
= 25 ns
c
= 35 ns
c
= 45 ns
c
= 5.5 V
CC
≥ V
-0.2 V
CC
≥ V
-0.2 V
CC
≤ 0.2 V
IL
≥ V
IH
CC
-0.2 V
= 5.5 V
≥ V
IH
4.5 5.5 V
-0.3 0.8 V
2.2 VCC+0.3 V
C-Type K-Type
Min. Max. Min. Max.
90
80
75
95
85
80
67mA
Unit
mA
mA
mA
t
= 25 ns
c
= 35 ns
t
c
= 45 ns
t
c
Average Supply Current
at t
= 200 ns
cR
(Cycling CMOS Input Levels)
Standby Supply Current
(Stable CMOS Input Levels)
b:I
and I
CC1
The current I
c:I
is the average current requird for the duration of the STORE cycle (STORE Cycle Time).
CC2
d: Bringing E
table. The current I
b
d
are dependent on output loading and cycle rate. The specified values are obtained with outputs unloaded.
CC3
is measured for WRITE/READ - ratio of 1/2.
CC1
≥ VIH will not produce standby current levels until any nonvolatile cycle in progress has timed out. See MODE SELECTION
is measured for WRITE/READ - ratio of 1/2.
CC(SB)1
I
CC(SB)
December 12, 1997
I
CC3
V
= 5.5 V
CC
≥ V
W
≤ 0.2 V
V
IL
≥ V
V
IH
V
= 5.5 V
CC
≥ V
E
≤ 0.2 V
V
IL
≥ V
V
IH
3
CC
CC
CC
CC
-0.2 V
-0.2 V
-0.2 V
-0.2 V
30
23
20
34
27
23
mA
mA
mA
15 15 mA
11mA
U631H64
DC Characteristics Symbol Conditions
Output High Voltage
Output Low Voltage
Output High Current
Output Low Current
Input Leakage Current
Output Leakage Current
High at Three-State- Output
Low at Three-State- Output
High
Low
V
V
I
I
OH
OL
I
OH
I
OL
I
IH
I
IL
OHZ
OLZ
V
CC
I
OH
I
OL
V
CC
V
OH
V
OL
V
CC
V
IH
V
IL
V
CC
V
OH
V
OL
= 4.5 V
=-4 mA
= 8 mA
= 4.5 V
= 2.4 V
= 0.4 V 8
= 5.5 V
= 5.5 V
= 0 V -1
= 5.5 V
= 5.5 V
= 0 V -1
SRAM MEMORY OPERATIONS
Switching Characteristics
No.
Read Cycle
1 Read Cycle Time
2 Address Access Time to Data Valid
f
g
3 Chip Enable Access Time to Data Valid t
4 Output Enable Access Time to Data Valid t
5E
HIGH to Output in High-Z
6G
HIGH to Output in High-Z
h
h
7E LOW to Output in Low-Z t
8G
LOW to Output in Low-Z t
9 Output Hold Time after Addr. Change
g
10Chip Enable to Power Activee t
11Chip Disable to Power Standby
d, e
Symbol 25 35 45
Alt.IECMin.Max.Min.Max.Min.Max.
t
AVAVtcR
t
AVQVta(A)
ELQVta(E)
GLQVta(G)
t
EHQZtdis(E)
t
GHQZtdis(G)
ELQXten(E)
GLQXten(G)
t
AXQXtv(A)
t
ELICCH
t
EHICCL
PU
t
PD
C-Type K-Type
Unit
Min. Max. Min. Max.
2.4
0.4
-4
1
1
2.4
-1
-1
8
0.4VV
-4 mA
mA
1 µA
µA
1 µA
µA
Unit
25 35 45 ns
25 35 45 ns
25 35 45 ns
12 20 25 ns
13 17 20 ns
13 17 20 ns
555ns
000ns
333ns
000ns
25 35 45 ns
e: Parameter guaranteed but not tested.
f: Device is continuously selected with E
g:Address valid prior to or at the same time with E
h:Measured ± 200 mV from steady state output voltage.
and G both LOW.
transition LOW.
4
December 12, 1997