ETC DS1813R-10

DS1813
5V EconoReset with Pushbutton
www.dalsemi.com
FEATURES
PIN ASSIGNMENT
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 surfacemount SOT-23 packages available
Efficient open-drain output with internal
5.5 kΩ=pull-up resistor
Operating temperature -40°C to +85°C
3
1
2
SOT-23 PACKAGE
1 2 3
1 2 3
TO-92 PACKAGE
See Mech.
Drawings Section
PIN DESCRIPTION
TO-92
1
2
3
RST
VCC
GND
Active Low Reset Output
Power Supply
Ground
SOT-23
1
2
3
RST
VCC
GND
Active Low Reset Output
Power Supply
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.
1 of 5
Powered by ICminer.com Electronic-Library Service CopyRight 2003
111999
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 150 µs 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 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
2 of 5
Powered by ICminer.com Electronic-Library Service CopyRight 2003
DS1813
TIMING DIAGRAM: PUSHBUTTON RESET Figure 3
TIMING DIAGRAM: POWER-UP Figure 4
TIMING DIAGRAM: POWER-DOWN Figure 5
3 of 5
Powered by ICminer.com Electronic-Library Service CopyRight 2003
DS1813
ABSOLUTE MAXIMUM RATINGS*
Voltage on VCC Pin Relative to Ground
Voltage on RST Relative to Ground
Operating Temperature
Storage Temperature
Soldering Temperature
*
-0.5V to +7.0V
-0.5V to +5VCC +0.5V
-40°C to +85°C
-55°C to +125°C
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
PARAMETER
Supply Voltage
SYMBOL
VCC
DC ELECTRICAL CHARACTERISTICS
PARAMETER
MIN
0.0
MIN
Output Current @ 0.4 volts
IOL
+10
Voltage Input Low
VIL
Voltage Input High
VIH
Operating Current VCC < 5.5
ICC
VCC Trip Point (DS1813-5)
VCCTP
VCC Trip Point (DS1813-10)
VCC Trip Point (DS1813-15)
Output Capacitance
MAX
5.5
UNITS
V
TYP
MAX
0.4
0.7
*VCC
UNITS
NOTES
mA
2, 3
V
1
V
1
40
µA
4
4.50
4.62
4.75
V
1
VCCTP
4.25
4.35
4.49
V
1
VCCTP
4.00
4.13
4.24
V
1
RP
3.50
5.5
7.5
k
6
10
pF
COUT
(-40°C to +85°C; VCC=1.2V to 5.5V)
SYMBOL
MIN
TYP
MAX
UNITS
RESET Active Time
tRST
100
150
300
ms
VCC Detect to RST
tRPD
2
5
µs
VCC Slew Rate
(VCCTP (MAX) - VCCTP (MIN))
tF
300
µs
VCC Slew Rate
(VCCTP (MIN) - VCCTP (MAX))
tR
0
ns
VCC Detect to RST
tRPU
100
Pushbutton Detect to RST
tPB
1
tPBRST
100
Pushbutton Reset
4 of 5
Powered by ICminer.com Electronic-Library Service CopyRight 2003
NOTES
1
30
AC ELECTRICAL CHARACTERISTICS
PARAMETER
TYP
(-40°C to +85°C; VCC=1.2V to 5.5V)
SYMBOL
Internal Pull-Up Resistor
(-40°C to +85°C)
150
300
ms
µs
150
300
ms
NOTES
7
5
DS1813
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%
5 of 5
Powered by ICminer.com Electronic-Library Service CopyRight 2003