MAXIM DS1813 User Manual

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DS1813

5V EconoReset with Pushbutton

GENERAL DESCRIPTION

The DS1813 EconoReset uses a precision
temperature reference and comparator circuit to
monitor the status of the power supply (VCC).
When an out-of-tolerance condition is detected,
an internal power-fail signal is generated which
forces reset to the active state. When VCC returns
to an in-tolerance condition, the reset signal is
kept in the active state for approximately 150ms
to allow the power supply and processor to
stabilize.

The DS1813 also monitors a pushbutton on the
reset output. If the reset line is pulled low, a reset
is generated upon release and will be held in reset
output low for typically 150ms.

FEATURES

 Automatically Restarts a Microprocessor

After Power Failure

 Monitors Pushbutton for External Override
 Maintains Reset for Typically 150ms After

VCC Returns to an In-Tolerance Condition

 Reduces Need for Discrete Components
 Precision Temperature-Compensated Voltage

Reference and Voltage Sensor

 Low-Cost TO-92 or Space-Saving Surface-

Mount SOT-23 Packages Available

 Efficient Open-Drain Output with Internal

5.5kΩ Pullup Resistor

 -40°C to +85°C Operating Temperature

PIN CONFIGURATIONS

DALLAS

DS1813

Econo
Reset

1 2 3

12

TOP VIEW

SOT-23 PACKAGE

See Mech.

Drawings Section

On Website

1 2 3

BOTTOM VIE

TO-92 PACKAGE

See Mech.

Drawings Section

On Website

PIN DESCRIPTION

PIN

TO-92 SOT-23

1 1

2 2 VCC Power Supply

3 3 GND Ground

NAME FUNCTION

RST

Active-Low
Reset Output

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DS1813

OPERATION—POWER MONITOR

The DS1813 provides the functions of detecting out-of-tolerance power-supply conditions and warning a
processor-based system of impending power failure. When VCC is detected as out-of-tolerance, the RST
signal is asserted. On power-up, RST is kept active for approximately 150ms after the power supply has
reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST
is released.

OPERATION—PUSHBUTTON RESET

The DS1813 provides for a pushbutton switch for manual reset control. When the DS1813 is not in a reset
cycle, a pushbutton reset can be generated by pulling the RST pin low for at least 1µs. When the
pushbutton is held low, the RST is forced active low and will remain active low for about 150ms after the
pushbutton is released. See Figure 2 for an application example and Figure 3 for the timing diagram.

Figure 1. Block Diagram (Open-Drain Output)

Figure 2. Application Example

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