MITSMI MM1075XF, MM1075XD Datasheet

MITSUMI

System Reset (with built-in watchdog timer) MM1075

System Reset (with built-in watchdog timer)

Monolithic IC MM1075

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

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

7. Timer monitoring time can be varied by using an external resistor

CC=0.8V typ.

Package

DIP-8A (MM1075XD)
SOP-8A (MM1075XF)

Applications

Microcomputer system monitoring, etc.

Absolute Maximum Ratings

Item Symbol Rating Units

Storage temperature T

Operating temperature T

Power supply voltage V

Voltage applied to VS & CK pins V

Voltage applied to RESET, RESET

Allowable loss Pd 400 mW

--------------------------------------------------------------

(Ta=25°C)

pin

STG

OPR

CC max.

VS &VCK

VOH

-

40~+125

-

20~+70

-

0.3~+10 V

-

0.3~+10 V

-

0.3~+10 V

°

C

°

C

MITSUMI

System Reset (with built-in watchdog timer) MM1075

Electrical Characteristics (DC)

Item Symbol

Consumption current I

Detection voltage

Detection voltage

temperature coefficient

Hysteresis voltage V

CK input threshold V

CK input current

Output voltage (High)

Output voltage (Low)

V

S/ T 1 ±0.01 %/

V

V

V

V

V

Measurement

circuit

CC 1 During watchdog timer operation 0.7 1.0 mA

V

SL 1 4.05 4.20 4.35

SH 1 4.15 4.30 4.45

V

HYS 1 50 100 150 mV

TH 1 0.8 1.2 2 V

I

IH 1VCK=5V 0 1

IL 1VCK=0V

I

OH11 I=

OH21 I=

OL1 1 I =3mA, VS=0V 0.2 0.4

OL2 1 I =10mA, VS=0V 0.3 0.5

OL31 IRESET=0.5mA, VS=OPEN 0.2 0.4

(Except where noted otherwise, Ta=25°C, VCC=5V)

Measurement conditions Min. Typ. Max. Units

VS=OPEN, VCC

VS=OPEN, VCC

VSH-VSL, VCC

-

20-10

----------------------------------------------------------------

RESET

-

5µA, VS=OPEN 4.5 4.8

----------------------------------------------------------------

RESET

-

5µA, VS=0V 4.5 4.8

----------------------------------------------------------------

RESET

----------------------------------------------------------------

RESET

V

°

C

µA

-

3

V

V

V

OL41 IRESET=1mA, VS=OPEN 0.3 0.5

I

OL1 1 V =1.0V, VS=0V 10 16

Output sink current

I

OL21 VRESET=1.0V, VS=OPEN 1 2

CT11

I

T charge current

C

1

*

I

CT21

Minimum operating power supply

voltage to ensure RESET

----------------------------------------------------------------------------

VCCL1 1 0.8 1.0 V

Minimum operating power supply

VCCL21

voltage to ensure RESET

----------------------------------------------------------------

RESET

V

TC=1.0V, RCT=OPEN during

watchdog timer operation

V

TV=1.0V during power ON

reset operation

----------------------------------------------------------------

RESET

V =0.4V

----------------------------------------------------------------

RESET

I =0.2mA

VRESET=VCC-0.1V

R

L2 (between Pin 2 and GND)

-

0.8-1.2-2.4 µA

-

0.8-1.2-2.4 µA

0.8 1.0 V

mA

MITSUMI

System Reset (with built-in watchdog timer) MM1075

Electrical Characteristics (AC)

(Except where noted otherwise, Ta=25°C, VCC=5V)

Measurement

Item Symbol

CC input pulse width TP12 8 µS

V

CK input pulse width T

CK input cycle T

Watchdog timer

monitoring time

2 RCT=OPEN

*

Reset time for

watchdog timer

3

*

Reset hold time for

power supply rise

4

*

Output delay time T

from V

CC

5 TPD22

*

Output rise time R

6

*

Output fall time R

6

*

CKW 23µS

CK 220µS

T

WD 2

WR 2CT=0.1µF

T

PR 2 50 100 150 mS

T

PD12

R12

t

t

R22

F12

t

t

F22

circuit

Measurement conditions Min. Typ. Max. Units

5V

VCC

4V

CK or

T=0.1µF

C

50 100 150 mS

123mS

T=0.1µF, VCC

C

RESET pin

RL1=2.2kΩ, CL1=100pF

RESET pin

R1, 2=10kΩ, C

L2=20pF

RESET pin

L1=2.2kΩ, CL1=100pF

RESET pin

R

L2=10kΩ, CL2=20pF

RESET pin

L1=2.2kΩ, CL1=100pF

RESET pin

R

L2=10kΩ, CL2=20pF

210

310

1.0 1.5 µS

1.0 1.5 µS

0.1 0.5 µS

0.5 1.0 µS

µS

Notes:

1ICT1 changes according to RCT pin (Pin 6) pull up resistance.

*

2 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. Also,
monitoring time can be varied by pulling up the R

CT pin to VCC with a resistor (RCT). Monitoring time

adjustments are shown in Graph 1.

3 Reset time means reset pulse width. However, this does not apply to power ON reset.

*

4 Reset hold time is the time from when VCC exceeds detection voltage (VSH) during power ON reset until

*

reset release (RESET

5 Output delay time is the time from when power supply voltage drops below detection voltage (VSI) until

*

6 Voltage range when measuring output rise and fall is 10~90%.

*

7 Watchdog timer monitoring time (TWD), watchdog timer reset time (TWR) and reset hold time (TPR) during

*

--------------------------------------------------------------

reset (RESET

power supply rise can be changed by varying C
formulae. The recommended range for C

--------------------------------------------------------------

output high, RESET output low).

output low, RESET output high).

T is 0.001~10µF.

T

PR (mS)

T

WD (mS)

T

WR (mS)

Example : When C

~

1000 CT (µF)

­~

1000 CT (µF)

­~

20 CT (µF)

-

T=0.1µF (RCT pin OPEN)

~

T

PR

100mS

­~

T

WD

100mS

-

~

T

WR

2mS

-

T capacitance. The times are expressed by the following