DS1833
5V EconoReset
www.dalsemi.com
FEATURES
Automatically restarts microprocessor after
power failure
Maintains active-high reset for 350 ms after
V
CC
returns to an in-tolerance condition
Accurate 5%, 10% or 15% microprocessor 5V
power supply monitoring
Reduces need for discrete components
Precision temperature-compensated voltage
reference and voltage sensor
Low-cost TO-92 package or surface mount
SOT-223 package
Internal 5k pull-up resistor
Operating temperature of -40掳C to +85掳C
PIN ASSIGNMENT
DALLAS
DS1833
1
1 2 3
1 2 3
TO-92 PACKAGE
See Mech.
Drawings Section
2 4 3
SOT-223 PACKAGE
See Mech.
Drawings Section
PIN DESCRIPTION
PIN 1
PIN 2
PIN 3
PIN 4
Ground
Reset
V
CC
Ground (SOT-223 only)
DESCRIPTION
The DS1833 EconoReset uses a precision temperature compensated reference and comparator circuit to
monitor the status of the power supply (V
CC
). When an out-of-tolerance condition is detected, an internal
power fail signal is generated which forces reset to the active (high) state. When V
CC
returns to an in-
tolerance condition, the reset signal is kept in the active state for approximately 350 ms to allow the
power supply and processor to stabilize.
OPERATION - POWER MONITOR
The DS1833 provides the functions of detecting out-of-tolerance power supply conditions and warning a
processor-based system of impending power failure. When V
CC
is detected as out-of-tolerance, as
defined by the tolerance of the part selected, the RST signal is asserted. On power-up, RST is kept active
for approximately 350 ms after the power supply has reached the selected tolerance. This allows the
power supply and microprocessor to stabilize before RST is released.
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