Dallas Semiconductor DS1810-5, DS1810-15, DS1810-10, DS1810X-10-T-R, DS1810R-5-T-R 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 surface

mount SOT-23 packages available

 Push-Pull output for low current operation
 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 DS1810 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 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.

DS1810

5V EconoReset with Push-Pull Output

www.dalsemi.com

12

3

SOT-23 PACKAGE

1 2 3

1 2 3

TO-92 PACKAGE

See Mech.

Drawings Section

DS1810

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OPERATION - POWER MONITOR

The DS1810 provides the function 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 pow er suppl y has
reached the selected tolerance. This allows the power supply and microprocessor to stabilize befor e RST

is released.

BLOCK DIAGRAM (PUSH-PULL OUTPUT) Figure 1

APPLICATION EXAMPLE Figure 2

OUTPUT VALID CONDITIONS

All versions of the DS1810 can maintain a valid output as long as VCC remains above 1.2 volt. However,
the

RST outputs on the DS1810 use a push-pull structure which can maintain a valid output below 1.2

volts on an input. To sink current below 1.2 volts, a resistor can be connected from RST to Ground (see
Figure 3). This arrangement will maintain a valid value on the

RST outputs even it V

CC

approaches 0

volts. During both power-up and -down this arrangement will draw current when

RST is in the high state.

A value of about 100 kኚ should be adequate to maintain a valid condition.