MITSUMI
System Reset (with built-in watchdog timer) MM1035
System Reset (with built-in watchdog timer)
Monolithic IC MM1035
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
V
CC
=0.8V typ.
3. Both positive and negative logic reset output can be extracted
4. Accurate detection of drop in power supply voltage
5. Detection voltage has hysteresis
6. Few external parts
1 capacitor
Package
DIP-8A (MM1035XD)
SOP-8A (MM1035XF)
Applications
Microcomputers
Absolute Maximum Ratings
(Ta=25
C)
Item
Symbol
Rating
Units
Storage temperature
T
STG
-40~+125
C
Operating temperature
T
OPR
-20~+70
C
Power supply voltage
V
CC
max.
-0.3~+10
V
Voltage applied to VS & CK pins
V
VS
& V
CK
-0.3~+10
V
Voltage applied to RESET, RESET pin
V
OH
-0.3~+10
V
Allowable loss
Pd
400
mW
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Electrical Characteristics 1 (DC)
(Except where noted otherwise, Ta=25C, V
CC
=5V, measurement circuit 1)
(Except where noted otherwise, resistance unit is
)
Item
Symbol
Measurement
Measurement conditions
Min. Typ. Max.
Units
circuit
Consumption current
I
CC
1
During watchdog timer operation
0.7
1.0
mA
Detection voltage
V
SL
1
4.05
4.20
4.35
V
V
SH
1
4.15
4.30
4.45
Detection voltage
V
S
/ T
1
0.01
%/
C
temperature coefficient
Hysteresis voltage
V
HYS
1
50
100
150
mV
CK input threshold
V
TH
1
0.8
1.2
2
V
CK input current
I
IH
1
V
CK
=5V
0
1
A
I
IL
1
V
CK
=0V
-20
-10
-3
Output voltage (High)
V
OH
1
1
I
=-5A, V
S
=OPEN
4.5
4.8
V
V
OH
2
1
I
RESET
=-5A, V
S
=0V
4.5
4.8
V
OL
1
1
I
=3mA, V
S
=0V
0.2
0.4
Output voltage (Low)
V
OL
2
1
I
=10mA, V
S
=0V
0.3
0.5
V
V
OL
3
1
I
RESET
=0.5mA, V
S
=OPEN
0.2
0.4
V
OL
4
1
I
RESET
=1mA, V
S
=OPEN
0.3
0.5
Output sink current
I
OL
1
1
V
=1.0V, V
S
=0V
10
16
mA
I
OL
2
1
V
RESET
=1.0V, V
S
=OPEN
1
2
I
CT
1
1
V
TC
= 1.0V during watchdog
-8
-12
-24
A
C
T
charge current
timer operation
I
CT
2
1
V
TV
= 1.0V during power
-0.8
-1.2
-2.4
A
on reset operation
Minimum operating power
V
CCL
1
1
0.8
1.0
V
supply voltage to ensure RESET
------------------------------------------------
Minimum operating power
V
CCL
2
1
I
RESET
=V
CC
-0.1V
0.8
1.0
V
supply voltage to ensure RESET
------------------------------------------------
R
L
2 (between Pin 2 and GND) =1M
RESET
-------------------------------------------
RESET
-----------------------------------------
RESET
-----------------------------------------
RESET
-----------------------------------------
V
S
=OPEN, V
CC
V
S
=OPEN, V
CC
V
=0.4V
I
=0.2mA
RESET
------------------------------------------------
RESET
--------------------------------------------
V
SH
-V
SL
, V
CC
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Electrical Characteristics 2 (AC)
(Except where noted otherwise, Ta=25C, V
CC
=5V, measurement circuit 2)
(Except where noted otherwise, resistance unit is
)
Item
Symbol
Measurement
Measurement conditions
Min. Typ. Max.
Units
circuit
V
CC
input pulse width
T
PI
2
8
s
CK input pulse width
T
CKW
2
3
s
CK input cycle
T
CK
2
20
s
Watchdog timer
T
WD
2
C
T
=0.1F
5
10
15
ms
monitoring time
*
1
Reset time for
T
WR
2
C
T
=0.1F
1
2
3
ms
watchdog timer
*
2
Reset hold time for
T
PR
2
50
100
150
ms
power supply rise
*
3
T
PD
1
2
RESET
---------------------------------------
pin
2
10
Output delay time from V
CC
R
L
1=2.2k, C
L
1=100pF
s
*
4
T
PD
2
2
RESET pin
3
10
R
L
2=10k, C
L
2=20pF
t
R
1
2
RESET
----------------------------------------
pin
1.0
1.5
Output rise time
R
L
1=2.2k, C
L
1=100pF
s
*
5
t
R
2
2
RESET pin
1.0
1.5
s
R
L
2=10k, C
L
2=20pF
V
CC
5V
4V
CK
or
C
T
=0.1F, 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
---------------------------------------
output goes high (reset release).
*
4: Output delay time is the time from when power supply voltage drops below detection voltage (V
SL
), until
RESET
---------------------------------------
output goes low (reset status).
*
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. The recommended range for C
T
is 0.001~10F.
T
PR
(ms)
.
=. 1000 C
T
(F)
Example : When C
T
=0.1F
T
WD
(ms)
.
=. 100 C
T
(F)
T
PR
.
=. 100ms
T
WR
(ms)
.
=. 20 C
T
(F)
T
WD
.
=. 10ms
T
WR
.
=. 2ms
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Block Diagram
Note 1: CP = 0.1F approx.
Note 2: C >
= 1000pF.
Note 3: The watchdog timer can be stopped by connecting the RCT pin to GND.
(Then it functions as a voltage detection circuit.)
Timing Chart
V
CC
CK
C
T
RESET
RESET
V
SH
V
SL
T
CK
T
PR
T
WD
T
WR
Pin Assignment
1
4
3
2
8
5
6
7
1
T
C
2
RESET
3
CK
4
GND
5
V
CC
6
RCT
7
V
S
8
RESET
-----------------------------------------
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Pin Description
Pin No.
Pin Name
Function
1
T
C
T
WD
, T
WR
, T
PR
variable pins. (T
WD
, T
WR
and T
PR
times are determined by
the external capacitor.)
2
RESET
Reset output pin (High output)
3
CK
Clock input pin (inputs clock from logic system)
4
GND
Reset output pin (High output)
5
V
CC
4.2V detection voltage
6
RCT
Watchdog timer stop pin
Operation modes: Operation OPEN, Stop connect to GND
7
VS
Detection voltage variable pin
Variation modes : Lower pull up resistance, Raise pull down
8
RESET
---------------------------------------------------------------
Reset output pin (Low output)
Measuring Circuit
Measuring Circuit 1 (DC)
Measuring Circuit 2 (AC)
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Measuring Circuit 1
SW Table 6-1-2. SW&Power Supply Table 1
Item
Symbol SW1 SW2 SW3 SW4 SW5 SW6 SW7 V
CC
V
CK
V
CT
I
I
RESET
VM, IM Notes
Consumption current
I
CC
OFF OFF OFF ON
B
B
ON
5V
5V
0V
-
-
I
CC
Detection voltage
V
SL
OFF OFF ON
ON
B
B
ON 5V 0V 3V
3V
-
-
V
O
1, CRT1
V
SH
OFF OFF ON
ON
B
B
ON 4V 5V 3V
3V
-
-
V
O
1, CRT1
CK input threshold
V
TH
OFF OFF OFF ON
B
B
ON
5V 0V 3V
1V
-
-
I
CK
CK input current
I
IH
OFF OFF OFF ON
B
B
ON
5V
5V
0V
-
-
I
CK
I
IL
OFF OFF OFF ON
B
B
ON
5V
0V
0V
-
-
I
CK
Output voltage (High)
V
OH
1
ON OFF ON
ON
B
B
ON
5V
5V
3V
-5A
-
V
O
1
V
OH
2
OFF ON
ON
ON
C
B
ON
5V
5V
3V
-
-5A
V
O
2
V
OL
1
ON
ON
ON
ON
B
B
ON
5V
5V
3V
3mA
-
V
O
1
Output voltage (Low)
V
OL
2
ON
ON
ON
ON
B
B
ON
5V
5V
3V
10mA
-
V
O
1
V
OL
3
OFF OFF ON
ON
C
B
ON
5V
5V
3V
-
0.5mA
V
O
2
V
OL
4
OFF OFF ON
ON
C
B
ON
5V
5V
3V
-
1mA
V
O
2
Output sink current
I
OL
1
OFF ON
ON
ON
B
C
ON
5V
5V
3V
-
-
I
O
1
V
OO
=1V
I
OL
2
OFF OFF ON
ON
B
A
ON
5V
5V
3V
-
-
I
O
2
V
OO
=1V
C
T
charge current 1
I
TC
1
OFF OFF OFF ON
B
B
OFF
5V
-
1V
-
-
I
TC
C
T
charge current 2
I
TC
2
OFF OFF ON
ON
B
B
OFF
5V
-
1V
-
-
I
TC
Minimum operating power supply
voltage to ensure reset
V
CCL
1
ON OFF ON
ON
B
B
ON 0V 2V 0V
0V
-
V
O
1, V
CC
Minimum operating power supply
voltage to ensure reset
V
CCL
2
OFF ON
ON
ON
A
B
ON 0V 2V 0V
0V
-
-
V
O
2, V
CC
RESET
----------------------------------------
Measuring Circuit 2
SW Table 6-2-2. SW&Power Supply Table 2
Item
Symbol SW1 SW2
V
CCA
V
CC
V
CKA
V
CK
CRT
Notes
V
CC
input pulse width
T
PI
C
B
-
-
CRT1,2,3
T1=8s
CK input pulse width T
CKW
A
B
5V
-
CRT1,2,3
T2=3s
CK input cycle
T
CK
A
B
5V
-
CRT1,2,3
T3=20s
Watchdog timer
monitoring time
T
WD
A
A
5V
5V
CRT1,2,3
Reset time for
watchdog timer
T
WR
A
A
5V
5V
CRT1,2,3
Reset hold time
for power supply rise
T
PR
B A
A
5V
5V
CRT1,2,3
T
PD
1
C
A
-
0V
CRT1,3
Output delay time
from V
CC
T
PD
2
C
A
-
0V
CRT2,3
Output rise time
T
R
1
A
A
5V
5V
CRT1
T
R
2
A
A
5V
5V
CRT2
Output fall time
T
P
1
A
A
5V
5V
CRT1
T
P
2
A
A
5V
5V
CRT2
5V
4V
T1
1.4V
0V
T2
T3
1.4V
0V
T2
T2
or
5V
0V
5V
0V
1.4V
0V
T2
T3
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Detection Voltage Variation 1
(lowering detection voltage)
Detection voltage can be changed by connecting
resistor R1 externally to MM1035 Vs pin. Determine
R1 according to graph 1 when changing Vs.
Vs pin external resistance
(R1) (k
)
4.0
3.5
3.0
100 200
300
400 500
600
V
SH
value
V
SL
value
Detection voltage
(Vs) (V)
Graph 1. Detection voltage change using MM1035 external resistor
Detection Voltage Variation 2
(raising detection voltage)
Detection voltage can be changed by connecting
resistor R2 externally to MM1035 Vs pin. Determine
R2 according to graph 2 when changing Vs.
5.0
4.5
100 200 300 400 500 600
Detection voltage
(Vs) (V)
Vs pin external resistance
(R1) (k
)
V
SH
value
V
SL
value
Graph 2. Detection voltage change using MM1035 external resistor
MITSUMI
System Reset (with built-in watchdog timer) MM1035
Characteristics
Power supply current-Power supply voltage
Clock pulse input time
1.4
1.2
1.0
0.8
0.6
0.4
0.2
1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
Power supply current Icc
(mA)
Power supply voltage V
CC
(V)
Output voltage-Power supply voltage (RESET pin)
7.0
6.0
5.0
4.0
3.0
2.0
1.0
1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
Ta=20
C.25
C.75
C
PULL UP resistance 10k
Power supply current Icc
(mA)
Power supply voltage V
CC
(V)
Output voltage-Power supply voltage (RESET
------------------------------------------------------------------
pin)
Ta=-25
C
Ta=25
C
Ta=75
C
7.0
6.0
5.0
4.0
3.0
2.0
1.0
1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0
PULL UP resistance 2.2k
Output voltage V
RESET
(V)
Power supply voltage V
CC
(V)
Detection voltage (V
SL
, V
SH
) temperature (RESET, RESET
---------------------------------------------------------------------------
pins)
4.50
4.40
4.30
4.20
4.10
4.00
3.00
-40 -20 0
20
40
60
80 100
Ambient temperature Ta (
C)
V
SH
V
SL
Detection voltage (V)
Output saturation voltage-Output sink current (RESET
----------------------------------------------------------------
pin)
Ta=75
C
Ta=25
C
Ta=-25
C
500
400
300
200
100
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8
Output saturation voltage
V
OL
(mV)
Output sink current I
OL
(mA)
Output saturation voltage-Output sink current (RESET
------------------------------------------------------------------------------
pin)
500
400
300
200
100
2
4
6
8
10 12 14 16 18
Ta=75
C
Ta=25
C
Ta=-25
C
Output saturation voltage
V
OL
(mV)
Output sink current I
OL
(mA)
MITSUMI
System Reset (with built-in watchdog timer) MM1035
High level output voltage-High level
output current (RESET pin)
5.0
4.8
4.6
4.4
4.2
4.0
3.8
-2 -4 -6 -8 -10-12-14-16-18
High level output voltage
V
OM
(V)
High level output current I
OM
(
A)
High level output voltage - High level output current
(RESET
------------------------------------------------
pin)
5.0
4.8
4.6
4.4
4.2
4.0
3.8
-2 -4 -6 -8 -10-12-14 -16 -18
High level output voltage
V
OM
(V)
High level output current I
OM
(
A)
Reset hold time temperature during power
supply rise
160
140
120
100
80
60
40
-40 -20 0
20 40
60
80 100
V
CC
=5V (Cr=0.1
F)
Reset hold time temperature during
power supply rise T
PR
(ms)
Ambient temperature Ta (
C)
Watchdog timer monitoring time temperature
16
14
12
10
8
6
4
-40 -20 0
20 40
60 80 100
V
CC
=5V (Cr=0.1
F)
Watchdog timer monitoring time
temperature T
WD
(ms)
Ambient temperature Ta (
C)
Reset time temperature (for watchdog timer)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
-40 -20 0
20 40
60
80 100
V
CC
=5V (Cr=0.1
F)
Reset time T
WR
(ms)
Ambient temperature Ta (
C)
C
T
value for reset hold time during power supply rise
10
5
10
4
10
3
10
2
10
1
10
-3
10
-2
10
-1
10
0
10
0
10
1
Hold time T
WD
(ms)
C
T
capacitance (
F)
MITSUMI
System Reset (with built-in watchdog timer) MM1035
C
T
value for reset time (for watchdog timer)
10
3
10
2
10
1
10
0
10
-1
10
-2
10
-3
10
-2
10
-1
10
0
10
1
Reset time T
WR
(ms)
C
T
capacitance (
F)
C
T
value for watchdog timer monitoring time
10
4
10
3
10
2
10
1
10
0
10
-1
10
-3
10
-2
10
-1
10
0
10
1
Timer monitoring time T
WD
(ms)
C
T
capacitance (
F)
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