MITSUMI
System Reset (with built-in watchdog timer) MM1095
System Reset (with built-in watchdog timer)
Monolithic IC MM1095
Outline
This IC functions in a variety of CPU systems and other logic systems to generate a reset signal and reset the
system accurately during momentary interruption or lowering of power supply voltage.
It also has a built-in watchdog timer for operation diagnosis. This prevents the system from running wild by
generating an intermittent reset pulse during system mis-operation.
Features
1. Built-in watchdog timer
2. Low minimum operating voltage
100A typ.
3. Low operating limit voltage
Vcc=0.8V
4. Watchdog stop function (RCT pin)
5. Few external parts
Package
DIP-8B (MM1095AD, MM1095BD)
SOP-8C (MM1095AF, MM1095BF)
SIP-8A (MM1095AS, MM1095BS)
Applications
1. Reset circuits in microcomputers, CPUs and MPUs
2. Logic circuit reset circuits
3. Microcomputer system monitoring, etc.
Pin Assignment
1
4
3
2
8
5
6
7
SOP-8C/DIP-8B
1
TC
2
NC
3
CK
4
GND
5
V
CC
6
RCT
7
V
S
8
RESET
------------------------------------------
SIP-8A
1
3
5
7
2
4
6
8
1
TC
2
NC
3
CK
4
GND
5
V
CC
6
RCT
7
V
S
8
RESET
------------------------------------------
MITSUMI
System Reset (with built-in watchdog timer) MM1095
Pin Description
Pin No.
Name
Function
1
TC
2
N.C
3
CK
4
GND
5
V
CC
6
RCT
7
V
S
8
RESET
------------------------------------------------------------------------------------
T
WD
, T
WR
, T
PR
variable pins
.
T
PR
(mS)=5000 C
T
(F)
(T
WD
, T
WR
and T
PR
times are determined
T
WD
(mS)=500 C
T
(F)
by the external capacitor.)
T
WR
(mS)=100 C
T
(F)
Clock input pin, inputs clock from logic system
GND pin
Voltage detection MM1095A 3.2V, MM1095B 4.2V
Watchdog timer stop pin Operation modes : Operation OPEN, Stop connect to GND
Detection voltage variable pin
Reset output pin (low output)
Absolute Maximum Ratings
Item
Symbol
Rating
Units
Power supply voltage
V
CC
max.
-0.3~+10
V
CK pin input voltage
V
CK
-0.3~V
CC
+0.3 ( <
= +10)
V
V
S
pin input voltage
V
VS
-0.3~V
CC
+0.3 ( <
= +10)
V
Voltage applied to RCT pin
V
RCT
-0.3~V
CC
+0.3 ( <
= +10)
V
Voltage applied to RESET
--------------------------------------------
pin
V
OH
-0.3~V
CC
+0.3 ( <
= +10)
V
Allowable loss
Pd
400
mW
Storage temperature
T
STG
-40~+125
C
Recommended Operating Conditions
Item
Symbol
Rating
Units
Power supply voltage
V
CC
+2.2~+7.0
V
RESET
-------------------------------------------
sync current
I
OL
0~1.0
mA
Clock monitoring time setting
T
WD
0.1~1000
mS
Clock rise and fall times
t
FC
, t
RC
<100
S
TC pin capacitance
C
T
0.0002~2
F
Operating temperature
T
OP
-25~+75
C
MITSUMI
System Reset (with built-in watchdog timer) MM1095
Electrical Characteristics (DC)
(Except where noted otherwise, MM1095A : Vcc=3.6V, Ta = 25C, MM1095B: Vcc=5.0V)
Item
Symbol
Measurement conditions
Min.
Typ.
Max.
Units
Consumption
MM1095A
I
CC
During watchdog timer operation
100
150
current
MM1095B
130
195
A
MM1095A
V
SL
3.10
3.20
3.30
Detection
MM1095B
4.05
4.20
4.35
V
voltage
MM1095A
V
SH
3.15
3.25
3.35
MM1095B
4.15
4.30
4.45
Detection voltage
V
S
/ T
0.01
%/
C
temperature coefficient
Hysteresis voltage
MM1095A
V
HYS
25
50
100
mV
MM1095B
50
100
150
CK input threshold
V
TH
0.8
1.2
2
V
CK input current
I
IH
A : V
CK
=3.6V, B : V
CK
=5.0V
0
1
A
I
IL
V
CK
=0V
-12
-6
-2
Output voltage MM1095A
V
OH
I
=-1A
3.0
3.4
V
(High)
MM1095B
V
S
=OPEN
4.0
4.5
Output voltage (Low)
V
OL
1
I
=0.5mA, V
S
=0V
0.2
0.4
V
V
OL
2
I
=1.0mA, V
S
=0V
0.3
0.5
R output sync current
I
OL
V
=1.0V, V
S
=0V
1
2
mA
C
T
charge current
I
CT
1
V
TC
=1.0V during watchdog timer operation
-1.60
-2.40
-4.80
A
I
CT
2
V
TC
=1.0V during power ON reset operation
-0.16
-0.24
-0.48
A
Minimum operating power
supply voltage to ensure RESET
--------------------------------------------------------------------------
V
CCL
0.8
1.0
V
RESET
------------------------------------------
RESET
------------------------------------------
RESET
------------------------------------------
RESET
------------------------------------------
V
S
=OPEN, V
CC
V
S
=OPEN, V
CC
V
=0.4V
I
=0.1mA
RESET
------------------------------------------
RESET
------------------------------------------
V
SH
-V
SL
, V
CC
MITSUMI
System Reset (with built-in watchdog timer) MM1095
Electrical Characteristics (DC)
(Except where noted otherwise, MM1095A : V
CC
=3.6V, Ta=25C, MM1095B : V
CC
=5.0V)
Item
Symbol Measurement
conditions
Min.
Typ.
Max.
Units
MM1095A
8
V
CC
input
T
PI
S
pulse width
MM1095B
8
CK input pulse width
T
CKW
3
S
CK input cycle
T
CK
20
S
Watchdog timer
monitoring time
*
1
T
WD
C
T
=0.02F
5
10
15
mS
Reset time for
watchdog timer
*
2
T
WR
C
T
=0.02F
1
2
3
mS
Reset hold time for
power supply rise
*
3
T
PR
50
100
150
mS
Output delay time from V
CC
*
4
T
PD
RESET
-------------------------------------------------------------------------------
pin, R
L
=10k
, C
L
=20pF
2
10
S
Output rise time
*
5
t
R
RESET
-------------------------------------------------------------------------------
pin, R
L
=10k
, C
L
=20pF
2.0
4.0
S
Output fall time
*
5
t
F
RESET
-------------------------------------------------------------------------------
pin, R
L
=10k
, C
L
=20pF
0.2
1.0
S
V
CC
3.6V
2.8V
V
CC
5.0V
4.0V
C
T
=0.02F, V
CC
V
CC
Notes:
*
1 Monitoring time is the time from the last pulse (negative edge) of the timer clear clock pulse until reset
pulse output. In other words, reset output is output if a clock pulse is not input during this time.
*
2 Reset time means reset pulse width. However, this does not apply to power ON reset.
*
3 Reset hold time is the time from when V
CC
exceeds detection voltage (V
SH
) during power ON reset until
reset release (RESET
-------------------------------------------------------------------------------
output high).
*
4 Output delay time is the time from when power supply voltage drops below detection voltage (V
SL
) until
reset (RESEToutput low).
*
5 Voltage range when measuring output rise and fall is 10~90%.
*
6 Watchdog timer monitoring time (T
WD
), watchdog timer reset time (T
WR
) and reset hold time (T
PR
) during
power supply rise can be changed by varying C
T
capacitance. The times are expressed by the following
formulae.
T
PR
(mS)
.
=. 5000 C
T
(F)
T
WD
(mS)
.
=. 500 C
T
(F)
T
WR
(mS)
.
=. 100 C
T
(F)
Example: When C
T
=0.02F
T
PR
.
=. 100mS
T
WD
.
=. 10mS
T
WR
.
=. 2mS
CK
or
MITSUMI
System Reset (with built-in watchdog timer) MM1095
Measuring Circuits
Measuring Circuit 1(DC)
Measuring Circuit 2 (AC)
Measuring Circuit 1
SW & Power Supply Table
Item
Symbol SW1 SW2 SW3 SW4 SW5 SW6 SW7
V
CC
V
CK
V
CT
I
VM, IM
Notes
Consumption current
I
CC
OFF
OFF
OFF
ON
ON
ON
A
3.6V
3.6V
0V
-
I
CC
Detection voltage
V
SL
OFF
OFF
ON
ON
ON
ON
A
3.6V 3V
0V
2V
-
V
O1
, CRT1
V
SH
OFF
OFF
ON
ON
ON
ON
A
3V 3.6V
0V
2V
-
V
O1
, CRT1
CK input threshold
V
TH
OFF
OFF
OFF
ON
ON
ON
A
3.6V 0V 3V
1V
-
I
CK
, V
CK
CK input current
I
IH
OFF
OFF
OFF
ON
ON
ON
A
3.6V
3.6V
0V
-
I
CK
I
IL
OFF
OFF
OFF
ON
ON
ON
A
3.6V
0V
0V
-
I
CK
Output voltage (High)
V
OH
ON
OFF
ON
ON
ON
ON
A
3.6V
3.6V
2V
-1A
V
O
1
Output voltage (Low)
V
OL
1
ON
ON
ON
ON
ON
ON
A
3.6V
3.6V
2V
0.5mA
V
O
1
V
OL
2
ON
ON
ON
ON
ON
ON
A
3.6V
3.6V
2V
1.0mA
V
O
1
Output sink current
I
OL
1
OFF
ON
ON
ON
ON
ON
B
3.6V
3.6V
2V
-
I
O
1
V
O
=1V
C
T
charge current 1
I
TC
1
OFF
OFF
OFF
ON
ON
OFF
A
3.6V
-
1V
-
I
TC
C
T
charge current 2
I
TC
2
OFF
OFF
OFF
ON
ON
OFF
A
3.6V
-
1V
-
I
TC
Minimum operating power
supply voltage to ensure RESET
--------------------------------------------------
V
CCL
ON
OFF
ON
ON
ON
ON
A
0V 2V
0V
0V
-
V
O1
, V
CC
RESET
-------------------------------------------------------
Measuring Circuit 2
SW & Power Supply Table
Item
Symbol SW1 SW2
V
CCA
V
CC
V
CKA
V
CK
CRT
Notes
V
CC
input pulse width
T
P
1
C
B
-
-
CRT1
T1=8S
CRT2
CK input pulse width T
CKW
A
B
-
3.6V
-
CRT1
T2=3S
CRT2
CK input cycle
T
CK
A
B
-
3.6V
-
CRT1
T3=20S
CRT2
Watchdog timer
T
WD
A
A
-
3.6V
-
3.6V
CRT1
monitoring time
CRT2
Reset time for
T
WR
A
A
-
3.6V
-
3.6V
CRT1
watchdog timer
CRT2
Reset hold time for
T
PR
B A
A
-
3.6V
-
3.6V
CRT1
power supply rise
CRT2
Output delay time
from V
CC
T
PD
C
A
-
-
0V
CRT1
Output rise time
T
R
A
A
-
3.6V
-
3.6V
CRT1
Output fall time
T
F
A
A
-
3.6V
-
3.6V
CRT1
3.6V
2.5V
T1
1.4V
0V
T2
T3
1.4V
0V
T2
T2
or
1.4V
0V
3.6V
0V
T2
T3
PDF 
ZIP