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122001

FEATURES

§ Halts and restarts an out-of-control

microprocessor

§ Holds microprocessor in check during power

transients

§ Automatically restarts microprocessor after

power failure

§ Monitors pushbutton for external override

§ Accurate 5%, 10%, or 20% (3V only)

microprocessor power monitoring

§ Eliminates the need for discrete components

§ 20% tolerance for use with 3.0V systems

§ Pin- and function-compatible with the

MAX823/24/25 products

§ Low cost SOT-23-5 package

§ Industrial temperature range: -40°C to +85°C

DEVICE

RST

RST

PBRST

WD

DS181xA

DS181xB

DS181xC

X

X

X

X

X

X

X

X

X

x = "DS1814" for 5V devices

x = "DS1819" for 3V devices

PIN ASSIGNMENT

PIN DESCRIPTION

DS181xA

1

RST

Active Low Reset Output

2

GND

Ground

3

PBRST

Pushbutton Reset Input

4

ST

Strobe Input

5

VCC

Power Supply

DS181xB

1

RST

Active Low Reset Output

2

GND

Ground

3

RST

Active High Reset Output

4

ST

Strobe Input

5

VCC

Power Supply

DS181xC

1

RST

Active Low Reset Output

2

GND

Ground

3

RST

Active High Reset Output

4

PBRST

Pushbutton Reset Input

5

VCC

Power Supply

DESCRIPTION

The DS1814 5-Volt MicroMonitor and the DS1819 3.3V MicroMonitor monitor three vital conditions for

a microprocessor: power supply, software execution, and external override. First, a precision temperature-

condition occurs, an internal power-fail signal is generated which forces the reset(s) to an active state.

140ms to allow the power supply and processor to stabilize.

DS1814/DS1819

5V and 3.3V MicroMonitor

www.maxim-ic.com

32

1

45

SOT-23-5 PACKAGE

See Mech. Drawing