Harman Kardon HK 990/230, Руководство по обслуживанию

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041002
FEATURES
§
Automatically restarts a microprocessor after
power failure
§
Monitors pushbutton for external override
§
Maintains reset for 150 ms after V
CC
returns
to an in-tolerance condition
§
Reduces need for discrete components
§
Precision temperature-compensated voltage
reference and voltage sensor
§
Accurate 5%, 10% or 20% power monitoring
§
Low-cost TO-92 or space saving surface
mount SOT-23 packages available
§
Efficient open-drain output with internal
5.5 k
W
pull-up resistor
§
Operating temperature -40
°
C to +85
°
C
PIN ASSIGNMENT
PIN DESCRIPTION
TO-92
1
RST
Active Low Reset Output
2 V
CC
Power Supply
3 GND Ground
SOT-23
1
RST
Active Low Reset Output
2 V
CC
Power Supply
3 GND Ground
DESCRIPTION
The DS1818 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 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.
The DS1818 also monitors a pushbutton on the reset output. If the reset line is pulled low, a reset is
generated upon release and the DS1818 output will be held in reset output low for typically 150 ms.
DS1818
3.3V EconoReset with Pushbutton
www.maxim-ic.com
1 2
3
TOP VIEW
SOT-23 PACKAGE
See Mech.
Drawings Section
On Website
1 2 3
1 2 3
BOTTOM VIEW
TO-92 PACKAGE
See Mech.
Drawings Section
On Website
DALLAS
DS1818
Econo
Reset
4 4