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FEATURES
Automatically restarts a microprocessor after
power failure
Monitors pushbutton for external override
Maintains reset for typically 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
Efficient open-drain output with internal
5.5 kΩ=pull-up resistor
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 VCC Power Supply
3 GND Ground
DESCRIPTION
The DS1813 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 VCC 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 DS1813 also monitors a pushbutton on the reset output. If the reset line is pulled low, a reset is
generated upon release and will be held in reset output low for typically 150 ms.
DS1813
5V EconoReset with Pushbutton
www.dalsemi.com
12
3
SOT-23 PACKAGE
1 2 3
1 2 3
TO-92 PACKAGE
See Mech.
Drawings Section
DS1813
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OPERATION - POWER MONITOR
The DS1813 provides the functions of detecting out-of-tolerance power supply conditions and warning a
processor-based s ystem of impending power failure. W hen VCC is detected as out-of-tolerance, the RST
signal is asserted. On power-up, RST is kept active for approximately 150 µs after the power supply has
reached the selected tolera nce. This allows the power supply and microprocessor to stabilize befor e RST
is released.
OPERATION - PUSHBUTTON RESET
The DS1813 provides for a pushbutton switch for manual reset control. When the DS1813 is not in a reset
cycle, a pushbutton reset can be generated by pulling the RST pin low for at least 1 ms. When the
pushbutton is held low, the RESET is forced active low and will remain active low for about 150 ms after
the pushbutton is released. See Figure 2 for an application example and Figure 3 for the timing diagram.
BLOCK DIAGRAM (OPEN-DRAIN OUTPUT) Figure 1
APPLICATION EXAMPLE Figure 2
DS1813
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TIMING DI AGRAM: PUSHBUTTON RESET Figure 3
TIMING DI AGRAM: POWER-UP Figure 4
TIMING DI AGRAM: POWER-DOWN Figure 5
DS1813
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ABSOLUTE MAXIMUM RATINGS*
Voltage on VCC Pin Relative to Ground -0.5V to +7.0V
Voltage on RST Relative to Ground -0.5V to +5VCC +0.5V
Operating Temperature -40°C to +85°C
Storage Temperature -55°C to +125°C
Soldering Temperature 260°C for 10 seconds
* This is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
RECOMMENDED DC OPERATING CONDITIONS (-40°C to +85 °C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Supply Voltage VCC 0.0 5.5 V 1
DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Output Current @ 0.4 volts IOL +10 mA 2, 3
Voltage Input Low VIL 0.4 V 1
Voltage Input High VIH 0.7
*VCC
V1
Operating Current VCC < 5.5 ICC 30 40 µA4
VCC Trip Point (DS1813-5) VCCTP 4.50 4.62 4.75 V 1
VCC Trip Point (DS1813-10) VCCTP 4.25 4.35 4.49 V 1
VCC Trip Point (DS1813-15) VCCTP 4.00 4.13 4.24 V 1
Internal Pull-Up Resistor RP3.50 5.5 7.5 k 6
Output Capacitance COUT 10 pF
AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=1.2V to 5.5V)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
RESET Active Time tRST 100 150 300 ms
VCC Detect to RST tRPD 25µs
VCC Slew Rate
(VCCTP (MAX) - VCCTP (MIN))
tF300 µs7
VCC Slew Rate
(VCCTP (MIN) - VCCTP (MAX))
tR0ns
VCC Detect to RST tRPU 100 150 300 ms 5
Pushbutton Detect to RST tPB 1µs
Pushbutton Reset tPBRST 100 150 300 ms
DS1813
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NOTES:
1. All voltages are referenced to ground.
2. Measured with VCC ≥ 2.7 volts.
3. A 1kΩ=external resistor may be required in some applications for proper operation of the
microprocessor reset control circuit.
4. Measured with RST output open.
5. tR = 5 µs.
6. VOH and IOH are a function of the value of RP and the associated output load conditions.
7. This value is for reference in defining values for TRPD and should not be considered a requirement for
proper operation or use of the device.
PART MARKING CODES
“A”, “B”, &“C” represent the device type.
810 . . . . DS1810
811 . . . . DS1811
812 . . . . DS1812
813 . . . . DS1813
815 . . . . DS1815
816 . . . . DS1816
817 . . . . DS1817
818 . . . . DS1818
“D” represents the device tolerance.
A . . . . . . 5%
B . . . . . . 10%
C . . . . . . 15%
D . . . . . . 20%
