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
di
sc
on
I
O
=10µA
I
O
=70mA
I
O
=10mA
I
O
=120mA
I
O
=120mA
to
be
uc
ts
Pr
Package
TSOP-20A (MM1027XV, MM1027NV, MM1081XV)
SOP-16A (MM1027XF, MM1027NF)
DIP-16A (MM1027XD)
od
-----------------------
---
tin
ue
0.3µA typ.
0.2V typ.
0.1µA max.
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.
d
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
TSOP-20A
GND
ADJ.
NC
TC
NC
CS
1
2
3
4
5
6
7
8
9
10
11
12
13
di
TC
CS
NC
-------------
-------------
be
-------------
-------------
NC
CS
NC
to
DET.CONT
Bat.DET1
NC
Bat.DET2
Battery
V
OUT
External drive
NC
V
CC
ts
DET.CONT
Bat.DET1
NC
Bat.DET2
NC
Battery
NC
V
OUT
NC
uc
od
14
15
Pr
16
17
18
19
20
External drive
V
CC
sc
on
SOP-16A
GND
NC
ADJ.
CS
Pin no.
Function
tin
DIP-16A
GND
NC
T
C
CS
NC
-------------
-------------
DET.CONT
Bat.DET1
NC
Bat.DET2
Battery
V
OUT
External drive
NC
V
CC
ue
ADJ.
CS
d
MITSUMI
System Reset (with battery back-up) MM1027, 1081
Block Diagram
Item
Storage temperature
Operating temperature
Power supply voltage
Operating voltage
Allowable loss
Output current
MM1027
MM1081
Symbol
T
STG
T
OPR
Rating
tin
7
7
300
90
120
200
H
Absolute Maximum Ratings
(Ta=25
°C
)
sc
on
-20~+70
V
CC
=5V, V
BAT
=3V, I
O
=0mA
D.CONT pin : OPEN
V
CC
=5V, V
BAT
=3V, I
O
=0mA
V
CC
=5V, V
BAT
=3V, I
O
=0mA
D.CONT pin : GND
L, V
BAT
=3V, ADJ pin : OPEN
V
CC
=L H
-40~+125
V
CC
max.
V
CCOP
Pd
I
O
1
di
I
O
1
I
O
2
be
Output current
Note : I
O
1 expresses V
CC
output current value, and I
O
2 expresses V
BATT
output current value.
uc
Item
Consumption
All
circuits
ts
Electrical Characteristics
to
(Except where noted otherwise, Ta=25°C, V
CC
=5V, V
BAT
=3V)
Symbol
I
CC
1
Measurement conditions
Min. Typ. Max. Units
0.9
150
1.2
1.7
3.0
mA
µA
mA
V
V
%/
°
C
V
V
V
V
µA
current 1
od
MM1027
MM1081
MM1027
I
CC
2
V
S
1
V
S
1
V
S
/
V
S
2
V
S
2
V
CSL
V
CSH
I
CSH
T
Pr
Consumption
ue
Units
°
C
°
C
d
V
V
mW
mA
mA
µA
210 350
2.2
3.5
current 2
CS, CS detection voltage 1
CS, CS hysteresis voltage 1
Detection voltage
-----------------
----------------
V
CC
=H
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
V
CC
=H
L, V
BAT
=3V
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
--------------
-------------
(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
)
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 L
--------------
-------------
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
V
BAT
=H
V
BAT
=L
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
VBD2
VBD2
VBDL
IBDSNK
IBDH
V
SAT
1
V
SAT
2
I
BUD
V
BB
V
BB
V
CC
=5V, R2=10kΩ PULL UP
V
BAT
=H
L (to V
CC
)
V
CC
=5V, R2=10kΩ PULL UP
sc
on
V
BAT
=L
H (to V
CC
)
V
CC
=5V, V
BAT
=0V
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
D.CONT pin : GND
D.CONT pin : OPEN
V
CC
=5V, V
TC
=0V
VBD1
V
CC
=5V, R1=10kΩ PULL UP
tin
VBD1
V
CC
=5V, R1=10kΩ PULL UP
di
ue
-
1.0
-
-
-
-
-
16
-
-
-
2.0
d
0.2
3.0
-
0.2
0.2
0.3
25
-
-
-
3.0
2.60 2.70 2.80
0.05 0.10 0.20
2.45 2.55 2.65
0.05 0.10 0.20
0.4
-
0.2
0.3
0.3
0.4
-
to
be
V
CC
=5V, V
BAT
=0V, VBD=4V
V
CC
=5V, V
BAT
=3V, VBD=5V
MM1081
0.25 0.4
External transistor driving current
uc
I/O voltage difference 3
ts
I/O voltage difference 2
V
SAT
3
od
Backup Power supply switching voltage
circuit Hysteresis voltage
unit
3.15 3.30 3.45
0.05 0.10 0.20
±0.08
±0.06
Pr
Switching voltage
MM1027
temperature characteristic MM1081
V
BB
/ T
I
LOS
I
OREV
I
TCSCE
V
CC
=0V, V
BAT
=3V, I
O
=0µA
V
CC
=0V, V
BAT
=3V, I
O
=0µA
Loss current
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
Pr
od
uc
ts
to
be
di
sc
on
tin
V
BD2
ue
V
BD1
d
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