HANBit
HMN2568D
Non-Volatile SRAM MODULE 2Mbit (256K x 8-Bit), 32Pin-DIP, 5V
Part No
. HMN2568D
GENERAL DESCRIPTION
The HMN2568D Nonvolatile SRAM is a 2,097,152-bit static RAM organized as 262,144 bytes by 8 bits.
The HMN2568D has a self-contained lithium energy source provide reliable non-volatility coupled with the unlimited write
cycles of standard SRAM and integral control circuitry which constantly monitors the single 5V supply for an out-of-
tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on to sustain the
memory until after V
CC
returns valid and write protection is unconditionally enabled to prevent garbled data. In addition the
SRAM is unconditionally write-protected to prevent an inadvertent write operation. At this time the integral energy source is
switched on to sustain the memory until after V
CC
returns valid.
The HMN2568D uses extremely low standby current CMOS SRAM’s, coupled with small lithium coin cells to provide non-
volatility without long write-cycle times and the write-cycle limitations associated with EEPROM.
FEATURES
w
Access time : 70, 85, 120, 150 ns
w
High-density design : 2Mbit Design
w
Battery internally isolated until power is applied
w
Industry-standard 32-pin 256K x 8 pinout
w
Unlimited write cycles
w
Data retention in the absence of V
CC
w
10-years minimum data retention in absence of power
w
Automatic write-protection during power-up/power-down
cycles
w
Data is automatically protected during power loss
w
Conventional SRAM operation; unlimited write cycles
PIN ASSIGNMENT
NC
A
16
A
14
A
12
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
DQ
0
DQ
1
DQ
2
V
SS
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
V
CC
A
15
A
17
/WE
A
13
A
8
A
9
A
11
/OE
A
10
/CE
DQ
7
DQ
6
DQ
5
DQ
4
DQ
3
OPTIONS
w
Timing
70 ns
85 ns
120 ns
150 ns
MARKING
- 70
- 85
-120
-150
32-pin Encapsulated Package
URL : www.hbe.co.kr
Rev. 0.0 (April, 2002)
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HANBit Electronics Co.,Ltd
HANBit
FUNCTIONAL DESCRIPTION
HMN2568D
The HMN2568D executes a read cycle whenever /WE is inactive(high) and /CE is active(low). The address specified by
the address inputs(A
0
-A
17
) defines which of the 262,144 bytes of data is accessed. Valid data will be available to the eight
data output drivers within t
ACC
(access time) after the last address input signal is stable.
When power is valid, the HMN2568D operates as a standard CMOS SRAM. During power-down and power-up cycles, the
HMN2568D acts as a nonvolatile memory, automatically protecting and preserving the memory contents.
The HMN2568D is in the write mode whenever the /WE and /CE signals are in the active (low) state after address inputs
are stable. The later occurring falling edge of /CE or /WE will determine the start of the write cycle. The write cycle is
terminated by the earlier rising edge of /CE or /WE. All address inputs must be kept valid throughout the write cycle. /WE
must return to the high state for a minimum recovery time (t
WR
) before another cycle can be initiated. The /OE control
signal should be kept inactive (high) during write cycles to avoid bus contention. However, if the output bus been enabled
(/CE and /OE active) then /WE will disable the outputs in t
ODW
from its falling edge.
The HMN2568D provides full functional capability for Vcc greater than 4.5 V and write protects by 4.37 V nominal. Power-
down/power-up control circuitry constantly monitors the Vcc supply for a power-fail-detect threshold V
PFD
. When V
CC
falls
below the V
PFD
threshold, the SRAM automatically write-protects the data. All inputs to the RAM become
“don’t
care” and
all outputs are high impedance. As Vcc falls below approximately 3 V, the power switching circuit connects the lithium
energy soure to RAM to retain data. During power-up, when Vcc rises above approximately 3.0 volts, the power switching
circuit connects external Vcc to the RAM and disconnects the lithium energy source. Normal RAM operation can resume
after Vcc exceeds 4.5 volts.
BLOCK DIAGRAM
PIN DESCRIPTION
/OE
/WE
256K x 8
SRAM
Block
Power
Power
–
Fail
Control
A
0
-A
17
DQ
0
-DQ
7
A
0
-A
17
: Address Input
/CE : Chip Enable
V
SS
: Ground
DQ
0
-DQ
7
: Data In / Data Out
/CE
CON
V
CC
/WE : Write Enable
/OE : Output Enable
V
CC
: Power (+5V)
NC : No Connection
/CE
Lithium
Cell
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TRUTH TABLE
MODE
Not selected
Output disable
Read
Write
/OE
X
H
L
X
/CE
H
L
L
L
/WE
X
H
H
L
I/O OPERATION
High Z
High Z
D
OUT
D
IN
HMN2568D
POWER
Standby
Active
Active
Active
ABSOLUTE MAXIMUM RATINGS
PARAMETER
DC voltage applied on V
CC
relative to V
SS
DC Voltage applied on any pin excluding V
CC
relative to V
SS
Operating temperature
Storage temperature
Temperature under bias
Soldering temperature
SYMBOL
V
CC
V
T
RATING
-0.3V to 7.0V
-0.3V to 7.0V
0 to 70°C
-40 to 85°C
-40°C to 70°C
-10°C to 70°C
260°C
For 10 second
V
T
≤
V
CC
+0.3
Commercial
Industrial
CONDITIONS
T
OPR
T
STG
T
BIAS
T
SOLDER
NOTE:
Permanent device damage may occur if Absolute Maximum Ratings are exceeded.
Functional operation should be restricted to the Recommended DC Operating Conditions detailed in this data sheet.
Exposure to higher than recommended voltage for extended periods of time could affect device reliability.
RECOMMENDED DC OPERATING CONDITIONS ( T
A
= T
OPR
)
PARAMETER
Supply Voltage
Ground
Input high voltage
Input low voltage
SYMBOL
V
CC
V
SS
V
IH
V
IL
MIN
4.5V
0
2.2
-0.3
TYPICAL
5.0V
0
-
-
MAX
5.5V
0
Vcc+0.3V
0.8V
NOTE:
Typical values indicate operation at T
A
= 25℃
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Rev. 0.0 (April, 2002)
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HANBit Electronics Co.,Ltd
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DC ELECTRICAL CHARACTERISTICS
(T
A
= T
OPR
, V
CCmin
£
V
CC
≤
V
CCmax
)
PARAMETER
Input Leakage Current
Output Leakage Current
Output high voltage
Output low voltage
Standby supply current
Standby supply current
CONDITIONS
V
IN
=V
SS
to V
CC
/CE=V
IH
or /OE=V
IH
or /WE=V
IL
I
OH
=-1.0mA
I
OL
= 2.1mA
/CE=V
IH
/CE≥ V
CC
-0.2V,
0V≤ V
IN
≤
0.2V,
or V
IN
≥
V
CC
-0.2V
Operating supply current
Power-fail-detect voltage
Supply switch-over voltage
NOTE:
Typical values indicate operation at T
A
= 25℃ .
Min.cycle,duty=100%,
/CE=V
IL
, I
I/O
=0㎃ ,
I
CC
V
PFD
V
SO
-
4.30
-
75
4.37
3
I
SB1
-
2.5
SYMBOL
I
LI
I
LO
V
OH
V
OL
I
SB
MIN
-
-
2.4
-
-
TYP.
-
-
-
-
5
HMN2568D
MAX
±
2
±
2
-
0.4
6
200
UNIT
mA
mA
V
V
㎃
mA
30
4.50
-
㎃
V
V
CAPACITANCE
(T
A
=25℃ , f=1MHz, V
CC
=5.0V)
DESCRIPTION
Input Capacitance
Input/Output Capacitance
CONDITIONS
Input voltage = 0V
Output voltage = 0V
SYMBOL
C
IN
C
I/O
MAX
10
10
MIN
-
-
UNIT
pF
pF
CHARACTERISTICS
(Test Conditions)
PARAMETER
Input pulse levels
Input rise and fall times
Input and output timing
reference levels
Output load
(including scope and jig)
VALUE
0 to 3V
5 ns
1.5V
( unless otherwise specified)
See Figures 1and 2
Figure 1.
Output Load A
Figure 2.
Output Load B
1KΩ
100㎊
1KΩ
5㎊
D
OUT
1.9KΩ
+5V
D
OUT
+5V
1.9KΩ
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HANBit Electronics Co.,Ltd
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READ CYCLE
(T
A
= T
OPR
, V
CCmin
£
V
CC
≤
V
CCmax
)
PARAMETER
Read Cycle Time
Address Access Time
Chip enable access time
Output enable to Output valid
Chip enable to output in low Z
Output enable to output in low Z
Chip disable to output in high Z
Output disable to output high Z
Output hold from address change
SYMBOL
t
RC
t
ACC
t
ACE
t
OE
t
CLZ
t
OLZ
t
CHZ
t
OHZ
t
OH
Output load A
Output load A
Output load A
Output load B
Output load B
Output load B
Output load B
Output load A
CONDITIONS
MIN
70
-
-
-
5
5
0
0
10
-70
MAX
-
70
70
35
-
-
25
25
-
MIN
85
-
-
-
5
0
0
0
10
-85
MAX
-
85
85
45
-
-
35
25
-
-120
MIN
120
-
-
-
5
0
0
0
10
MAX
-
120
120
60
-
-
45
35
-
HMN2568D
-150
MIN
150
-
-
-
10
5
0
0
10
MAX
-
150
150
70
-
-
60
50
-
UNIT
ns
ns
ns
ns
ns
ns
ns
ns
ns
WRITE CYCLE
(T
A
= T
OPR
, V
ccmin
£
V
cc
≤
V
ccmax
)
PARAMETER
Write Cycle Time
Chip enable to end of write
Address setup time
Address valid to end of write
Write pulse width
Write recovery time (write cycle 1)
Write recovery time (write cycle 2)
Data valid to end of write
Data hold time (write cycle 1)
Data hold time (write cycle 2)
Write enabled to output in high Z
Output active from end of write
SYMBOL
t
WC
t
CW
t
AS
t
AW
t
WP
t
WR1
t
WR2
t
DW
t
DH1
t
DH2
t
WZ
t
OW
Note 4
Note 4
Note 5
Note 5
Note 1
Note 2
Note 1
Note 1
Note 3
Note 3
CONDITIONS
MIN
70
65
0
65
55
5
15
30
0
10
0
5
-70
MAX
-
-
-
-
-
-
-
-
-
-
25
-
MIN
85
75
0
75
65
5
15
35
0
10
0
0
-85
MAX
-
-
-
-
-
-
-
-
-
-
30
-
-120
MIN
120
100
0
100
85
5
15
45
0
10
0
0
MAX
-
-
-
-
-
-
-
-
-
-
40
-
-150
Min
150
100
0
90
90
5
15
50
0
0
0
5
Max
-
-
-
-
-
-
-
-
-
-
50
-
UNI
T
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
NOTE:
1. A write ends at the earlier transition of /CE going high and /WE going high.
2. A write occurs during the overlap of allow /CE and a low /WE. A write begins at the later transition of /CE
going low and /WE going low.
3. Either t
WR1
or t
WR2
must be met.
4. Either t
DH1
or t
DH2
must be met.
5. If /CE goes low simultaneously with /WE going low or after /WE going low, the outputs remain in high-
impedance state.
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Rev. 0.0 (April, 2002)
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HANBit Electronics Co.,Ltd
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