Dallas Semiconductor DS1811R-5-T-R, DS1811R-15-T-R, DS1811R-10-T-R, DS1811-5, DS1811-15 Datasheet

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FEATURES

 Automatically restarts a microprocessor after

power failure

 Maintains reset for 150 ms 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 SOT-23

packages available

 Efficient open-drain output with internal

5.5 kΩ pull-up resistor

 Operating temperature -40°C to +85°C

PIN ASSIGNMENT

PIN DESCRIPTION
TO-92

1 RST Active Low Reset Output
2 VCC Power Supply
3 GND Ground

SOT-23

1 RST Active Low Reset Output
2 V

CC

Power Supply

3 GND Ground

DESCRIPTION

The DS1811 EconoReset uses a precision temperature reference and comparator circuit to monitor the
status of the power supply (V

CC

). When an out-of-tolerance condition is detected, an intern al power-fail

signal is generated which forces reset to t he active state. When V

CC

returns to an in-tolerance condition,
the reset signal is kept in the active state for approximately 150 ms to allow the power supply and
processor to stabilize.

DS1811

5V EconoReset with Open Drain Output

www.dalsemi.com

12

3

SOT-23 PACKAGE

1 2 3

1 2 3

TO-92 PACKAGE

See Mech.

Drawings Section

DS1811

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OPERATION - POWER MONITOR

The DS1811 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, th e RST
signal is asserted. On power-up, RST is kept active for approximately 150 ms after the power suppl y has
reached the selected tolerance. This allows the power supply and microprocessor to stabilize befor e RST

is released.

BLOCK DIAGRAM (OPEN-DRAIN OUTPUT) Figure 1

APPLICATION EXAMPLE Figure 2