MITSUMI
System Reset (with battery back-up) MM1027, 1081
System Reset (with battery back-up)
Monolithic IC MM1027, 1081
Outline
These ICs were developed for STATIC-RAM (S-RAM) battery back-up, and have built-in switching circuit for
main power supply and battery, back-up timing circuit and battery checker.
Power ON/OFF and momentary power interruptions can damage S-RAM data on equipment that contains an
S-RAM. These ICs switch the S-RAM to back-up mode (CS signal makes S-RAM CE pin low and CE pin high)
when power supply voltage goes below a set voltage (detection voltage 4.2V typ., variable), preventing
damage to data. Further, when power supply voltage drops, these ICs switch from main power supply to
battery back-up (switching voltage 3.3V typ.). Then, when power supply voltage rises, they first switch the S-
RAM from battery back-up state to main power supply (switching voltage 3.3V typ.), and from back-up mode
to normal mode (CS signal makes S-RAM CE pin high and CE pin low). These signal processes provide
reliable protection against data damage. The CS signal also can absorb power supply chattering and
roughness through the external capacitor.
There is a built-in battery checker to monitor the back-up battery voltage, and this circuit is turned ON/OFF by
the control pin.
-------------
-------------
-------------
------------
Features
1. Battery back-up
1. Low IC current consumption (loss current)
2. Drop voltage inside IC (input/output voltage difference)
3. Reverse current (reverse leak current)
2. Normal operation
MM1027
Drop voltage inside IC (input/output voltage difference)
Output voltage
V
CC
=5V
Current consumption
D.CONT OPEN
External transistor drive current
MM1081
Drop voltage inside IC (input/output voltage difference)
Output voltage
V
CC
=5V
Current consumption
External transistor drive current (for output current increase)
TC source current
3. Battery-Vcc switching voltage
4. Detection voltage (CS, CS) variable
5. Battery checker 1
X type
N type
6. Battery checker 2
X type
N type
------------------------
I
O
=10µA
0.3µA typ.
0.2V typ.
0.1µA max.
I
O
=70mA
I
O
=10mA
0.2V typ.
4.8V typ.
3.0mA max.
25mA typ.
0.25V typ.
4.75V typ.
350µA max.
25mA typ.
3.0µA typ.
3.3V typ.
4.2V typ.
2.70V typ.
2.50V typ.
2.55V typ.
2.35V typ.
I
O
=120mA
I
O
=120mA
Package
TSOP-20A (MM1027XV, MM1027NV, MM1081XV)
SOP-16A (MM1027XF, MM1027NF)
DIP-16A (MM1027XD)
MITSUMI
System Reset (with battery back-up) MM1027, 1081
Applications
1.
2.
3.
4.
IC memory cards (RAM cards)
PCs, word processors
Fax machines, photocopiers, other office equipment
Other equipment with S-RAMs (equipment requiring back-up)
Pin Assignment
16 15 14 13 12 11 10 9
20 19 18 17 16 15 14 13 12 11
1 2 3 4 5 6 7 8
SOP-16A/DIP-16A
1 2 3 4 5 6 7 8 9 10
TSOP-20A
Pin no.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Function
TSOP-20A
GND
ADJ.
NC
TC
NC
CS
NC
-------------
-------------
SOP-16A
GND
NC
ADJ.
TC
CS
NC
-------------
-------------
DIP-16A
GND
NC
ADJ.
T
C
CS
NC
-------------
-------------
CS
CS
CS
NC
DET.CONT
Bat.DET1
NC
Bat.DET2
NC
Battery
NC
V
OUT
NC
External drive
V
CC
DET.CONT
Bat.DET1
NC
Bat.DET2
Battery
V
OUT
External drive
NC
V
CC
DET.CONT
Bat.DET1
NC
Bat.DET2
Battery
V
OUT
External drive
NC
V
CC
MITSUMI
System Reset (with battery back-up) MM1027, 1081
Block Diagram
Absolute Maximum Ratings
Item
Storage temperature
Operating temperature
Power supply voltage
Operating voltage
Allowable loss
Output current
(Ta=25
°C
)
Symbol
T
STG
T
OPR
V
CC
max.
V
CCOP
Pd
I
O
1
I
O
1
I
O
2
Rating
-40~+125
-20~+70
7
7
300
90
120
200
Units
°
C
°
C
V
V
mW
mA
mA
µA
MM1027
MM1081
Output current
Note : I
O
1 expresses V
CC
output current value, and I
O
2 expresses V
BATT
output current value.
Electrical Characteristics
Item
Consumption
All
circuits
(Except where noted otherwise, Ta=25°C, V
CC
=5V, V
BAT
=3V)
Symbol
Measurement conditions
V
CC
=5V, V
BAT
=3V, I
O
=0mA
I
CC
1
D.CONT pin : OPEN
V
CC
=5V, V
BAT
=3V, I
O
=0mA
I
CC
2
V
S
1
V
S
1
V
S
/
V
S
2
V
S
2
V
CSL
V
CSH
I
CSH
T
V
CC
=H
L, V
BAT
=3V
H
V
CC
=5V, V
BAT
=3V, I
O
=0mA
D.CONT pin : GND
V
CC
=H
L, V
BAT
=3V, ADJ pin : OPEN
V
CC
=L H
Min. Typ. Max. Units
0.9
150
1.2
1.7
3.0
mA
µA
mA
V
V
%/
°
C
V
V
V
V
µA
MM1027
MM1081
MM1027
current 1
Consumption
current 2
210 350
2.2
3.5
CS, CS detection voltage 1
CS, CS hysteresis voltage 1
Detection voltage
-----------------
----------------
4.05 4.20 4.35
0.05 0.10 0.20
±0.08
±0.06
MM1027
temperature characteristic MM1081
CS
•
CS
circuit
CS, CS detection voltage 2
unit
ADJ pin : 12kΩ PULL UP (to V
CC
)
V
CC
=L
V
CC
=3V, I
CS
=3µA
V
CC
=5V, I
CS
=-3µA
V
CC
=5V, V
CS
=4.6V current measured
3.25 3.50 3.75
0.05 0.10 0.20
0.05 0.10
4.85 4.95
8
15
CS, CS hysteresis voltage 2
CS output voltage L
CS output voltage H
CS source current
MITSUMI
System Reset (with battery back-up) MM1027, 1081
Electrical Characteristics
Item
CS sync current
CS output voltage L
--------------
-------------
--------------
-------------
(Except where noted otherwise, Ta=25°C, V
CC
=5V, V
BAT
=3V)
Symbol
I
CSL
V
CSL
I
CSL
--------------------------------
----------------------------------
-------------------------
Measurement conditions
V
CC
=3.5, V
CS
=0.4V Current measured
V
CC
=5V, I
CS
=3µA
V
CC
=4V, V
OUT
-V
CSH
, I
CS
=-3µA
V
CC
=5V, V
CS
=0.4V Current measured
Minimum power supply voltage at which
CS pin can hold low level V
CS
< 0.4V
=
V
CC
=L
V
CC
=H
V
CC
=L
V
CC
=H
H, TC : OPEN, C1=47pF
L, TC : OPEN, C1=47pF
H, TC : 1nF, C1=47pF
L, TC : 1nF, C1=47pF
L (to V
CC
)
H(to V
CC
)
L (to V
CC
)
H (to V
CC
)
Min. Typ. Max. Units
0.5
-
-
0.3
-
-
-
-
-
2.0
-
mA
V
V
mA
V
µS
µS
mS
µS
V
V
V
V
V
mA
µA
V
V
V
mA
V
V
%/
°
C
µA
µA
µA
0.10 0.25
0.14 0.40
1.0
2.0
30
2.0
0.8
2.0
-
2.4
-
5
-
10
CS output voltage H
--------------
-------------
V
CSH
CS sync current
--------------
-------------
CS CS
circuit Operation limit voltage L
unit
ON delay time 1
•
V
OPL
t
PLH
1
t
PHL
1
t
PLH
2
t
PHL
2
OFF delay time 1
ON delay time 2
OFF delay time 2
BATT
MM1027X
detection voltage 1 MM1081N
BATT hysteresis voltage 1
BD
BATT
MM1027X
VBD1
VBD1
VBD2
VBD2
VBDL
IBDSNK
IBDH
V
CC
=5V, R1=10kΩ PULL UP
V
BAT
=H
V
BAT
=L
V
BAT
=H
V
BAT
=L
V
CC
=5V, R1=10kΩ PULL UP
V
CC
=5V, R2=10kΩ PULL UP
V
CC
=5V, R2=10kΩ PULL UP
V
CC
=5V, V
BAT
=0V
V
CC
=5V, V
BAT
=0V, VBD=4V
V
CC
=5V, V
BAT
=3V, VBD=5V
V
CC
=5V, I
O
=70mA
V
CC
=5V, I
O
=120mA
V
BAT
=3V, I
O
=10µA
V
BAT
=3V, I
O
=100µA
V
CC
=5V, V (T
B
) =4.5V
V
CC
=H
V
CC
=L
L, V
BAT
=3V
H, V
BAT
=3V
2.60 2.70 2.80
0.05 0.10 0.20
2.45 2.55 2.65
0.05 0.10 0.20
-
1.0
-
-
-
-
-
16
0.2
3.0
-
0.2
0.2
0.3
25
0.4
-
0.2
0.3
0.3
0.4
-
circuit detection voltage 2 MM1081N
unit
BATT hysteresis voltage 2
BD output voltage L
BD output sink current
Leakage current
I/O voltage
difference 1
MM1027
MM1081
V
SAT
1
V
SAT
2
V
SAT
3
I
BUD
V
BB
V
BB
0.25 0.4
I/O voltage difference 2
I/O voltage difference 3
External transistor driving current
Backup Power supply switching voltage
circuit Hysteresis voltage
unit
Switching voltage
MM1027
3.15 3.30 3.45
0.05 0.10 0.20
-
-
±0.08
±0.06
temperature characteristic MM1081
Loss current
V
BB
/ T
I
LOS
I
OREV
I
TCSCE
V
CC
=0V, V
BAT
=3V, I
O
=0µA
D.CONT pin : GND
V
CC
=0V, V
BAT
=3V, I
O
=0µA
D.CONT pin : OPEN
V
CC
=5V, V
TC
=0V
-
-
2.0
-
-
3.0
0.3
0.1
5.0
Reverse current
TC source current
MITSUMI
System Reset (with battery back-up) MM1027, 1081
Timing Chart
V
S1
V
CC
V
S
V
BB
V
BD1
V
BB
V
BD2
V
BD2
V
BD1
V
BATT
V
OUT
CS
CS
V
BD1
V
BD2
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