MM1095AS [MITSUMI]
System Reset (with built-in watchdog timer); 系统复位（带内置看门狗定时器）
| 型号： | MM1095AS |
| 厂家： | 
MITSUMI ELECTRONICS, CORP. |
| 描述： | System Reset (with built-in watchdog timer) |
| 文件： | 总7页 (文件大小：171K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
System Reset (with built-in watchdog timer) MM1095
MITSUMI
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
3. Low operating limit voltage
4. Watchdog stop function (RCT pin)
5. Few external parts
100µA typ.
Vcc=0.8V
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
2
3
4
5
6
7
8
TC
NC
1
2
3
4
5
6
7
8
TC
NC
CK
CK
8
1
7
2
6
3
5
4
GND
VCC
GND
VCC
1 2 3 4 5 6 7 8
RCT
RCT
-
SIP 8A
VS
VS
------------------------------------------
RESET
------------------------------------------
RESET
-
-
SOP 8C/DIP 8B
System Reset (with built-in watchdog timer) MM1095
MITSUMI
Pin Description
Pin No. Name
Function
TWD, TWR, TPR variable pins
TPR (mS)=5000 CT (µF)
.
1
TC
(TWD, TWR and TPR times are determined
by the external capacitor.)
TWD (mS)=500 CT (µF)
TWR (mS)=100 CT (µF)
2
3
4
5
6
7
8
N.C
CK
Clock input pin, inputs clock from logic system
GND pin
GND
VCC
Voltage detection
MM1095A 3.2V, MM1095B 4.2V
RCT
Watchdog timer stop pin Operation modes : Operation OPEN, Stop
Detection voltage variable pin
connect to GND
VS
------------------------------------------------------------------------------------
RESET
Reset output pin (low output)
Absolute Maximum Ratings
Item
Symbol
VCC max.
VCK
Rating
-0.3~+10
Units
V
Power supply voltage
CK pin input voltage
VS pin input voltage
Voltage applied to RCT pin
Voltage applied to -R---------E---------S---------E--------T-------- pin
Allowable loss
<
-
-
-
-
0.3~VCC+0.3 ( +10)
V
=
<
VVS
0.3~VCC+0.3 ( +10)
V
=
<
VRCT
0.3~VCC+0.3 ( +10)
=
V
<
VOH
0.3~VCC+0.3 ( +10)
=
V
Pd
400
mW
°C
Storage temperature
TSTG
-40~+125
Recommended Operating Conditions
Item
Symbol
VCC
Rating
Units
V
Power supply voltage
+2.2~+7.0
0~1.0
-------------------------------------------
RESET sync current
IOL
mA
mS
µS
Clock monitoring time setting
Clock rise and fall times
TC pin capacitance
TWD
0.1~1000
<100
tFC, tRC
CT
0.0002~2
µF
°
C
Operating temperature
TOP
-25~+75
System Reset (with built-in watchdog timer) MM1095
MITSUMI
(Except where noted otherwise, MM1095A : Vcc=3.6V, Ta = 25°C, MM1095B: Vcc=5.0V)
Electrical Characteristics (DC)
Item
Symbol
Measurement conditions
Min. Typ. Max.
Units
Consumption MM1095A
100
130
150
195
ICC
During watchdog timer operation
µA
current
MM1095B
MM1095A
MM1095B
MM1095A
MM1095B
3.10
4.05
3.15
4.15
3.20
4.20
3.25
4.30
3.30
4.35
3.35
4.45
VSL
VSH
VS=OPEN, VCC
VS=OPEN, VCC
Detection
voltage
V
Detection voltage
°
VS/
T
0.01
%/ C
temperature coefficient
MM1095A
Hysteresis voltage
25
50
50
100
1.2
0
100
150
2
VHYS
VSH
-
VSL, VCC
mV
V
MM1095B
CK input threshold
VTH
IIH
0.8
A : VCK=3.6V, B : VCK=5.0V
1
CK input current
µA
IIL
VCK=0V
-12
-6
-2
------------------------------------------
RESET
Output voltage MM1095A
I
=
-1µA
3.0
4.0
3.4
4.5
0.2
0.3
2
VOH
V
V
(High)
MM1095B
VS=OPEN
------------------------------------------
RESET
VOL1
VOL2
IOL
I
I
=0.5mA, VS=0V
0.4
0.5
Output voltage (Low)
R output sync current
CT charge current
------------------------------------------
RESET
=1.0mA, VS=0V
------------------------------------------
RESET
V
=1.0V, VS=0V
1
mA
µA
µA
ICT1
ICT2
V
TC=1.0V during watchdog timer operation
-
-
1.60
-
-
2.40
-
4.80
V
TC=1.0V during power ON reset operation
0.16
0.24
-0.48
------------------------------------------
Minimum operating power
RESET
V
=0.4V
VCCL
0.8
1.0
V
--------------------------------------------------------------------------
------------------------------------------
supply voltage to ensure RESET
RESET
I
=0.1mA
System Reset (with built-in watchdog timer) MM1095
MITSUMI
CC
CC
(Except where noted otherwise, MM1095A : V =3.6V, Ta=25°C, MM1095B : V =5.0V)
Electrical Characteristics (DC)
Item
Symbol
Measurement conditions
Min. Typ. Max.
Units
3.6V
2.8V
5.0V
4.0V
MM1095A
MM1095B
8
VCC
VCC
VCC input
pulse width
TPI
µS
8
CK input pulse width
CK input cycle
TCKW
TCK
3
µS
µS
CK
or
20
Watchdog timer
TWD
TWR
TPR
CT=0.02µF
CT=0.02µF
5
1
10
2
15
3
mS
mS
mS
monitoring time 1
*
Reset time for
watchdog timer 2
*
Reset hold time for
50
100
150
CT=0.02µF, VCC
VCC
power supply rise 3
*
-------------------------------------------------------------------------------
Output delay time from VCC
4
TPD
tR
RESET pin, RL=10kΩ, CL=20pF
-------------------------------------------------------------------------------
2
10
4.0
1.0
µS
µS
µS
*
Output rise time 5
RESET pin, RL=10kΩ, CL=20pF
-------------------------------------------------------------------------------
2.0
0.2
*
Output fall time 5
tF
RESET pin, RL=10kΩ, CL=20pF
*
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 VCC exceeds detection voltage (VSH) 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 (VSL) until
reset (RESEToutput low).
*
5 Voltage range when measuring output rise and fall is 10~90%.
6 Watchdog timer monitoring time (TWD), watchdog timer reset time (TWR) and reset hold time (TPR) during
power supply rise can be changed by varying CT capacitance. The times are expressed by the following
formulae.
*
*
.
TPR (mS) = 5000 CT (µF)
.
.
TWD (mS) = 500 CT (µF)
.
.
TWR (mS) = 100 CT (µF)
.
Example: When CT=0.02µF
.
TPR = 100mS
.
.
TWD = 10mS
.
.
TWR = 2mS
.
System Reset (with built-in watchdog timer) MM1095
Measuring Circuit 2 (AC)
MITSUMI
Measuring Circuits
Measuring Circuit 1(DC)
SW & Power Supply Table
Measuring Circuit 1
-------------------------------------------------------
RESET
Item
Symbol SW1 SW2 SW3 SW4 SW5 SW6 SW7
V
CC
VCK
VCT
I
VM, IM
Notes
Consumption current
I
CC
OFF OFF OFF ON ON ON
OFF OFF ON ON ON ON
OFF OFF ON ON ON ON
OFF OFF OFF ON ON ON
OFF OFF OFF ON ON ON
OFF OFF OFF ON ON ON
ON OFF ON ON ON ON
ON ON ON ON ON ON
ON ON ON ON ON ON
OFF ON ON ON ON ON
OFF OFF OFF ON ON OFF
OFF OFF OFF ON ON OFF
A
A
A
A
A
A
A
A
A
B
A
A
3.6V 3.6V 0V
-
-
-
-
-
I
CC
V
SL
3.6V 3V 0V
3V 3.6V 0V
2V
2V
V
O1, CRT1
O1, CRT1
Detection voltage
CK input threshold
CK input current
V
SH
V
V
TH
3.6V 0V 3V 1V
3.6V 3.6V 0V
ICK, VCK
I
IH
IL
OH
ICK
I
3.6V 0V
0V
-
ICK
Output voltage (High)
Output voltage (Low)
V
3.6V 3.6V 2V
3.6V 3.6V 2V
3.6V 3.6V 2V
3.6V 3.6V 2V
-
1µA
V
V
V
O
O
O
1
1
1
VOL
1
2
0.5mA
VOL
1.0mA
Output sink current
CT charge current 1
CT charge current 2
Minimum operating power
IOL
ITC
ITC
1
-
-
-
I
O
1
VO=1V
1
2
3.6V
3.6V
-
-
1V
1V
I
TC
TC
I
VCCL
ON OFF ON ON ON ON
A
0V 2V 0V
0V
-
VO1, VCC
--------------------------------------------------
supply voltage to ensure RESET
SW & Power Supply Table
Measuring Circuit 2
Item
Symbol SW1 SW2
V
CCA
V
CC
V
CKA
V
CK
CRT
CRT1
CRT2
CRT1
CRT2
CRT1
CRT2
CRT1
CRT2
CRT1
CRT2
CRT1
CRT2
Notes
T2
T3
3.6V
2.5V
1.4V
0V
T1
V
CC input pulse width
TP
1
C
A
A
A
A
B
B
B
A
A
A
A
-
-
T1=8µS
T2
1.4V
0V
CK input pulse width
CK input cycle
TCKW
-
-
-
-
-
3.6V
3.6V
3.6V
3.6V
3.6V
-
-
T2=3µS
or
T2
T2
T3
1.4V
0V
TCK
-
T3=20µS
Watchdog timer
monitoring time
Reset time for
T
WD
-
-
-
-
3.6V
3.6V
3.6V
0V
TWR
watchdog timer
Reset hold time for
power supply rise
Output delay time
from VCC
TPR
B
A
3.6V
0V
TPD
C
CRT1
Output rise time
Output fall time
T
R
A
A
A
A
-
-
3.6V
3.6V
-
-
3.6V CRT1
3.6V CRT1
T
F
System Reset (with built-in watchdog timer) MM1095
MITSUMI
Block Diagram
RA
~ ~
RB
MM1095A
MM1095B
305k
~ ~
195k
150k
350k
Note 1 : CP=0.1µF 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
VCC
VSH
VSL
CK
CT
TCK
TPR
TWD
TPR
TWR
RESET
1
2
3
4
5
5
6
7
8
9
10
11 12
System Reset (with built-in watchdog timer) MM1095
MITSUMI
Description of Operation
-------------------------------------------------
1. RESET goes low when VCC rises to approximately 0.8V.
2. Capacitor CT charging starts when VCC rises to VSH (MM1095A = 3.25V, MM1095B = 4.3V). Output is in
.
.
.
.
reset state at this time.
---------------------------------------------
3. Output reset is released (RESET goes high) after a certain time (TPR), from when CT starts charging until
.
discharge (the time from when CT voltage reaches a certain threshold value 1 (= 1.4V) until CT voltage
.
.
drops to a certain threshold value 2 (= 0.2V). Approximately 1µA (VCC=0.8V) of pull up current is output
.
from RESET.
Reset hold time : TPR is as follows.
.
TPR (mS) = 5000 CT (µF)
.
CT charging starts again after reset release, and watchdog timer operation begins.
4. If a clock is input (negative edge trigger) to the CK pin during CT charging, charging switches to discharge.
.
5. Discharge switches to charging when CT voltage drops to a certain threshold value (= 0.2V). Steps 4 and 5
.
are repeated while a normal clock is input from the logic system.
6. Output goes to reset state (-R---------E---------S---------E---------T-------- goes low) when the clock ceases and CT voltage reaches reset ON
.
threshold value (= 1.4V).
.
The formula for CT charging time (TWD: watchdog timer monitoring time) until reset is output is as follows.
.
TWD (mS) = 500 CT (µF)
.
7. Watchdog timer reset time TWR is the discharge time until CT voltage drops to reset OFF threshold value
.
(= 0.2V). The formula is as follows.
.
.
TWR (mS) = 100 CT (µF)
.
After reset OFF threshold value is reached, output reset is released and CT starts charging. Thereafter,
steps 4 and 5 are repeated if a normal clock is input, and when the clock ceases, 6 and 7 are repeated.
.
.
8. Reset is output when VCC drops to VSL (MM1095A = 3.2V, MM1095B = 4.2V). CT is charged
.
.
simultaneously.
9. CT charging starts when VCC rises to VSH.
When Vcc drops momentarily, CT charging begins after the charge is first discharged, if the time from VCC
dropping below VSL until it rises to VSH is longer than the VCC input pulse width standard value TPI.
10.Output reset is released after VCC goes above VSH and after TPR, and the watchdog timer starts. Thereafter,
8~10 are repeated when VCC goes below VSL.
11.When power is OFF, reset is output if VCC goes below VSL.
12.When VCC drops to 0V, reset output is held until VCC reaches 0.8V.
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