dallas semiconductor DS1812 service manual
www.maxim-ic.com
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DS1812
5V EconoReset with Active
High Push-Pull Output
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 active high output
§ Operating temperature -40°C to +85°C
PIN ASSIGNMENT
DALLAS
DS1812
Econo
Reset
12
TOP VIEW
SOT-23 PACKAGE
See Mech.
Drawings Section
1 2 3
1 2 3
BOTTOM VIEW
TO-92 PACKAGE
See Mech.
Drawings Section
On Website
On Website
PIN DESCRIPTION
TO-92
1 RST Active High Reset Output
2 VCC Power Supply
3 GND Ground
SOT-23
1 RST Active High Reset Output
2 VCC Power Supply
3 GND Ground
DESCRIPTION
The DS1812 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 V
the reset signal is kept in the active state for approximately 150 ms to allow the power supply and
processor to stabilize.
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returns to an in-tolerance condition,
CC
DS1812
OPERATION - POWER MONITOR
The DS1812 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, the RST
signal is asserted. On power-up, RST is kept active for approximately 150 ms after the power supply has
reached the selected tolerance. This allows the power supply and microprocessor to stabilize before RST
is released.
BLOCK DIAGRAM (CMOS OUTPUT) Figure 1
APPLICATION EXAMPLE Figure 2
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