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DS1813
5V EconoReset with Pushbutton
GENERAL 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 150ms
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 150ms.
FEATURES
Automatically Restarts a Microprocessor
After Power Failure
Monitors Pushbutton for External Override
Maintains Reset for Typically 150ms 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
5.5kΩ Pullup Resistor
-40°C to +85°C Operating Temperature
PIN CONFIGURATIONS
DALLAS
DS1813
Econo
Reset
1 2 3
12
TOP VIEW
SOT-23 PACKAGE
See Mech.
Drawings Section
On Website
1 2 3
BOTTOM VIE
TO-92 PACKAGE
See Mech.
Drawings Section
On Website
PIN DESCRIPTION
PIN
TO-92 SOT-23
1 1
2 2 VCC Power Supply
3 3 GND Ground
NAME FUNCTION
RST
Active-Low
Reset Output
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DS1813
OPERATION—POWER MONITOR
The DS1813 provides the functions 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 150ms after the power supply has
reached the selected tolerance. This allows the power supply and microprocessor to stabilize before 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 1µs. When the
pushbutton is held low, the RST is forced active low and will remain active low for about 150ms after the
pushbutton is released. See Figure 2 for an application example and Figure 3 for the timing diagram.
Figure 1. Block Diagram (Open-Drain Output)
Figure 2. Application Example
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Figure 3. Timing Diagram: Pushbutton Reset
DS1813
Figure 4. Timing Diagram: Power-Up
Figure 5. Timing Diagram: Power-Down
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DS1813
ABSOLUTE MAXIMUM RATINGS
Voltage Range on VCC Pin Relative to Ground……………………………………………...-0.5V to +7.0V
Voltage Range on RST Relative to Ground………………………………….….……-0.5V to (VCC +0.5V)
Operating Temperature Range………………………………………………………………-40°C to +85°C
Storage Temperature Range……………………………………………………………….-55°C to +125°C
Soldering Temperature………………………………………….See IPC/JEDEC J-STD-020 Specification
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
(TA = -40°C to +85°C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Supply Voltage VCC 0 5.5 V 1
DC ELECTRICAL CHARACTERISTICS
(VCC = 1.2V to 5.5V, TA = -40°C to +85°C.)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Output Current at 0.4V IOL 10 mA 2, 3
Voltage Input Low VIL 0.4 V 1
Voltage Input High VIH
Operating Current VCC < 5.5 ICC 30 40
0.7 x
V
CC
V 1
µA
4
DS1813-5 4.50 4.62 4.75
VCC Trip Point
DS1813-10 4.25 4.35 4.49
DS1813-15
Internal Pullup Resistor RP 3.50 5.5 7.5
Output Capacitance C
V
CCTP
V 1
4.00 4.13 4.24
kΩ
10 pF
OUT
6
AC ELECTRICAL CHARACTERISTICS
(VCC = 1.2V to 5.5V, TA = -40°C to +85°C.)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Reset Active Time t
VCC Detect to RST
V
Slew Rate
CC
(V
CCTP(MAX
) - V
CCTP(MIN)
)
VCC Slew Rate
(V
CCTP(MIN)
- V
CCTP(MAX)
)
VCC Detect to RST t
Pushbutton Detect to RST
Pushbutton Reset t
100 150 300 ms
RST
2 5
t
RPD
300
t
F
0 ns
t
R
100 150 300 ms 5
RPU
1
t
PB
100 150 300 ms
PBRST
µs
µs
µs
7
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NOTES:
1) All voltages are referenced to ground.
2) Measured with VCC ≥ 2.7V.
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 = 5µs.
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 t
and should not be considered a requirement for
RPD
proper operation or use of the device.
PART MARKING CODES
DS1813
“A,” “B,” and “C” represent the device type.
810 . . . . DS1810
811 . . . . DS1811
812 . . . . DS1812
813 . . . . DS1813
815 . . . . DS1815
“D” represents the device tolerance.
A . . . . . . 5%
B . . . . . . 10%
C . . . . . . 15%
D . . . . . . 20%
816 . . . . DS1816
817 . . . . DS1817
818 . . . . DS1818
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Maxim/Dallas Semiconductor cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim/Dallas Semiconductor product.
No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
The Maxim logo is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Dallas Semiconductor Corporation.
© 2006 Maxim Integrated Products • Printed USA
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