MITSUMI MM1135

System Reset (with built-in watchdog timer) MM1135, MM1136
MITSUMI
System Reset (with built-in watchdog timer)
Monolithic IC MM1135, MM1136
Outline
These ICs were developed to drive low voltage batteries, and have a watchdog timer with built-in
microcomputer reset voltage detection circuit and low battery detection circuit.
A single reference voltage is used for low battery voltage detection and microcomputer reset voltage
.
detection, so detection voltage difference is uniform ( =. 0.2V). Further, there is a built-in watchdog timer for
operation diagnosis, which prevents the system from running wild by generating an intermittent reset pulse
during system mis-operation.
Features
1. Accurate voltage drop detection voltage
1. Low battery detection
3.4V±3%
2. Power supply voltage detection
3.2V±3%
3. Detection voltage error
0.2V±20mV 1-2
4. Hysteresis Both
50mV typ.
2. Watchdog function stop pin (can be made to function only as reset IC during VCC rise)
3. Low current consumption
150µA typ.
Package
SOP-8C (MM1135XF, MM1136XF)
Applications
1. 3V cordless telephones
2. Various types of small, handy equipment
Series Table
Model
MM1135
MM1136
VSLB
VSLR
3.4V
3.2V
TPR
TWD
TWR
100mS
10mS
2mS
100mS
100mS
2mS
*C =0.02µF
T
TPR : Reset hold time during VCC rise
TWD : Timer monitoring time
TWR : Reset time
VSLB : Battery check detection voltage
VSLR : Reset detection voltage
System Reset (with built-in watchdog timer) MM1135, MM1136
MITSUMI
Pin Assignment
TC
1
----------------------------------------------------------------------------------------
8
7
1
2
6
3
5
4
2
BC (RESET)
3
CK
4
GND
5
VCC
6
RCT
VS
7
----------------------------------------------------------------------------------------
SOP-8C
RESET
8
Pin Description
Pin No.
1
Pin name
TC
----------------------------------------------------------------------------------------
2
BC (RESET)
3
CK
4
GND
5
VCC
6
RCT
7
VS
----------------------------------------------------------------------------------------
8
Block Diagram
RESET
Function
TWD, TWR, TPR time setting pins.
Battery check output pin (RESET low level output) for 3.4V
Clock input pin
GND pin
Power supply voltage input pin
Watchdog timer stop pin
Operation
OPEN, Stop
connect to GND
Detection voltage fine adjustment pin
Reset output pin (low output)
System Reset (with built-in watchdog timer) MM1135, MM1136
MITSUMI
Absolute Maximum Ratings
Item
Symbol
Rating
Units
Power supply voltage
VCC max.
-0.3~+7
V
Voltage applied to input pin
VIN
-0.3~VCC+0.3 ( <= +7)
V
Voltage applied to output pin
VOUT
-0.3~VCC+0.3 ( <= +7)
V
Allowable loss
Pd
450
mW
Storage temperature
TSTG
-40~+125
°C
Recommended Operating Conditions
Item
Symbol
Rating
Units
Power supply voltage
VCC
+2.5~+6.5
V
RESET sync current
IOLR
0~1.5
mA
BC sync current
IOLC
0~1.5
mA
Clock input high level voltage
VCKH
1.4<
V
Clock input low level voltage
VCKL
<0.4
V
Clock monitoring time setting
TWD
1~1000
mS
Clock rise and fall times
tRCK, tFCK
<100
µS
Power supply voltage rise times
tRVCC
100<
µS
Power supply voltage fall times
tFVCC
50<
µS
TC pin capacitance
CT
0.002~2
µF
Operating temperature
TOP
-25~+75
°C
--------------------------------------------------
System Reset (with built-in watchdog timer) MM1135, MM1136
MITSUMI
Electrical Characteristics
(Except where noted otherwise, Ta=25°C, Vcc=3.8V)
Item
Symbol
Measurement conditions
Consumption current
ICC
No load
RESET detection voltage
VSLR
Detection voltage
VSR
temperature coefficient R
T
Hysteresis voltage R
VHYSR
BC detection voltage
VSLB
Detection voltage
VSB
temperature coefficient B
T
Hysteresis voltage B
Detection voltage difference
CK input threshold
VHYSB
VSL
VCC : High
Low
RCT : GND, VTC=OPEN
Min. Typ. Max. Units
3.10
200
280
µA
3.20
3.30
V
±0.01 ±0.05 %/°C
VCC : Low
High
RCT : GND, VTC=OPEN
VCC : High
Low, RLB=10kΩ
25
50
100
mV
3.30
3.40
3.50
V
±0.01 ±0.05 %/°C
VCC : Low
High, RLB=10kΩ
VSL=VSLB-VSLR
VTH
25
50
100
mV
0.18
0.20
0.22
V
0.8
1.2
2
V
0
1
-15
-6
-2
IIH
VCK=3.8V
IIL
VCK=0.0V
Output voltage RH
VOHR
IRESET=-5µA
---------------------------------------------------
3.0
3.4
V
Output voltage BH
VOHB
RLB=10kΩ
3.2
3.6
V
CK input current
Output voltage RL
VOLR
Output voltage BL
VOLB
---------------------------------------------------
µA
IRESET=1mA, VCC=3.0V
0.3
0.5
V
IBC=5mA, VCC=3.0V
0.3
0.5
V
---------------------------------------------------
Output sync current R
IOLR
VRESET=0.5V, VCC=3.0V
1
2
mA
Output sync current B
IOLB
VBC=0.5V, VCC=3.0V
5
10
mA
8
15
µA
Output source current R
CT charge current
Minimum operating power supply
-----------------------------------------------
voltage to ensure RESET
IOHR
---------------------------------------------------
VRESET=3.4V
ICT1
VTC=1.0V during watchdog timer operation -0.48 -0.24 -0.16
µA
ICT2
VTC=1.0V during power ON reset operation -0.48 -0.24 -0.16
µA
---------------------------------------------------
VCC
VRESET=0.4V
---------------------------------------------------
IRESET=0.1mA
0.8
1.0
V
System Reset (with built-in watchdog timer) MM1135, MM1136
MITSUMI
3.8V
VCC input pulse width
TPI
VCC
CK input pulse width
TCKW
CK
CK input cycle
TCK
CK
Watchdog timer monitoring time 1
*
Watchdog timer
reset time 2
2.8V
TPI
TCKW
or
TCK
8
µS
3
µS
20
µS
TWD
CT=0.02µF
50
100
150
mS
TWR
CT=0.02µF
1
2
3
mS
TPR
CT=0.02µF
50
100
150
mS
*
Reset hold time for
power supply rise 3
*
------------------------------------------
RESET delay time
tPDR
VCC : High
Low, RLR=10kΩ, CLR=15pF
10
µS
BC delay time
tPDB
VCC : High
Low, RLB=4.7kΩ, CLB=15pF
10
µS
------------------------------------------
tRR
RLR=10kΩ, CLR=15pF
10
µS
RESET fall time
tFR
RLR=10kΩ, CLR=15pF
2
µS
BC rise time
tRB
RLB=4.7kΩ, CLB=15pF
10
µS
BC fall time
tFB
RLB=4.7kΩ, CLB=15pF
2
µS
RESET rise time
------------------------------------------
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 (VSHR) during power ON reset until
reset release (RESET output high).
4 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) .=. 5000 CT (µF)
TWR (mS) .=. 100 CT (µF)
Example : When CT=0.02µF
TPR .=. 100mS
TWD .=. 100mS
TWR .=. 2mS
5 TWD can be varied by placing a resistor (1MEGΩ or more) between the RCT pin and VCC.
6 The voltage range when measuring output rise and fall time is 10~90%.
7 VCC rise time should be 100µS or more, and fall time should be 50µS or more.
*
*
*
*
*
*
*
-----------------------------------------------------
System Reset (with built-in watchdog timer) MM1135, MM1136
MITSUMI
Measuring Circuit
Timing Chart
VSHB
VCC VSLB
VSMR
VSLR
0.8V
CK
TCKW
TCK
CT
RESET
TPR
TWR TWD
BC
RCT
Undefined
Basic Circuit Diagram