UM809_15 Datasheet, PDF (1/14 Pages) Union Semiconductor, Inc. – 3-Pin Microprocessor Reset Circuits

UM809/810
3-Pin Microprocessor Reset Circuits
UM809/810 SOT323/SOT23-3
General Description
The UM809/810 series are ultra low current, cost effective system supervisory circuits designed to
monitor the power supplies in digital systems. They provide a reset signal to the host processor
when necessary, offer excellent circuit reliability & low cost by eliminating external component
and adjustment when used with +5V, +3.3V, +3.0V or other voltage powered circuits.
The reset output is driven active within 10µs of power supply falling through the reset voltage
threshold. Reset is keeping active for a minimum of 140ms after system power supply has risen
above the reset threshold. Reset threshold suitable for operation with variety of supply voltage are
available.
UM809 has an active-low reset output while UM810 has an active-high reset output. The
UM809/810 are optimized to reject fast transient glitches on the power supply line, and the reset
output are guaranteed to be in the correct logic state for power supply V_CC down to 1V.
Each of these ICs consists of a voltage reference comparator, resistors for detector threshold
setting, delay generator, output driver & hysteresis circuit. The reset threshold & time delay are
fixed with high accuracy internally and does not require any external adjustment.
Low supply current of 3µA (V_CC=3V) makes UM809/810 ideal for low power application. Both
devices are available in 3 Pin SOT323 or SOT23 packages.
Applications
Features
 CPU and Logic Circuit Reset
 Power Fail Detectors
 Computers
 Embedded Systems
 Battery-Powered Equipments
 Intelligent Instruments
 Wide Operation Voltage Range of 1V to 10V
 Typical Quiescent Current of 3μA
 No External Components
 3-Pin Small SOT323 and SOT23 Packages
 V_CC Transient Immunity
 Correct Logic Output Guaranteed to V_CC=1.0V
 Precision V_CC Monitor for 2.5V, 3.0V, 3.3V,
and 5.0V Supplies
 Available in 2 Output Configurations
Push-Pull Low Active Reset Output (UM809)
Push-Pull High Active Reset Output (UM810)
 Wide Operation Temperature: -40°C to +85°C
Pin Configurations
Top View
3
GND 1
RESET 2
(RESET)*
3 VCC
( )* for UM810
XXX
Marking Pin1
1
2
M: Month Code
UM809/810
SOT323/SOT23-3
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http://www.union-ic.com Rev.06 Apr.2015
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