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3
DS1233D
5V EconoReset
FEATURES
PIN ASSIGNMENT
§ Automatically restarts microprocessor after
power failure
§ Maintains reset for 350 ms after VCC returns
to an in-tolerance condition
DALLAS
DS1233
Econo
Reset
1
§ Accurate 5%, 10% or 15% microprocessor 5V
power supply monitoring
§ Reduces need for discrete components
§ Precision temperature-compensated voltage
reference and voltage sensor
§ Low-cost TO-92 package or surface mount
1 2 3
4
2
TOP VIEW
SOT-23 PACKAGE
See Mech.
Drawings Section
On Website
SOT-223 package
§ Internal 5 kW pull-up resistor
§ Compatible with Motorola 68XXX series and
HC16 Microprocessors
§ Operating temperature of -40°C to +85°C
1 2 3
BOTTOM VIEW
TO-92 PACKAGE
See Mech.
Drawings Section
On Website
PIN DESCRIPTION
PIN 1 GROUND
PIN 2 RESET
PIN 3 V
CC
PIN 4 GROUND (SOT-223 ONLY)
DESCRIPTION
The DS1233D EconoReset uses a precision temperature-compensated 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 V
condition, the reset signal is kept in the active state for approximately 350 ms to allow the power supply
and processor to stabilize.
returns to an in-tolerance
CC
OPERATION - POWER MONITOR
The DS1233D 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 as
defined by the tolerance of the part selected, the
for approximately 350 ms after the power supply has reached the selected tolerance. This allows the
power supply and microprocessor to stabilize before
RST signal is asserted. On power-up, RST is kept active
RST is released.
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BLOCK DIAGRAM Figure 1
APPLICATION EXAMPLE Figure 2
DS1233D
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POWER UP Figure 3
POWER DOWN Figure 4
DS1233D
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DS1233D
ABSOLUTE MAXIMUM RATINGS*
Voltage on VCC Pin Relative to Ground -0.5V to +7.0V
Voltage on I/O Relative to Ground -0.5V to VCC +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 V
CC
1.2 5.0 5.5 V 1
DC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VDD=5V ± 10%)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Low Level @ RST
V
Output Current @ 0.4V I
Operating Current I
VCC Trip Point 5% V
VCC Trip Point 10% V
VCC Trip Point 15% V
CCTP1
CCTP2
CCTP3
Output Capacitance C
Internal Pull-Up Resistor R
OL
OL
CC
OUT
P
+8 mA 2
4.5 4.625 4.74 V 1
4.25 4.375 4.49 V 1
4.0 4.125 4.24 V 1
3.75 5 6.25
0.4 V 1
50
mA
10 pF
kW
AC ELECTRICAL CHARACTERISTICS (-40°C to +85°C; VCC=5V ± 10%)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Reset Active Time t
VCC Detect to RST
t
RST
RPD
250 350 450 ms
100 ns
V
Slew Rate (4.75V - 4.00V) t
CC
VCC Slew Rate (4.00V - 4.75V) t
VCC Detect to RST t
F
R
RPU
300
ms
0ns
250 350 450 ms
NOTES:
1. All voltages are referenced to ground.
2. A 1 kW external resistor may be required for proper operation of the microprocessor reset control
circuit.
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ECONORESET SELECTION GUIDE
VCC TRIP POINT PUSHBUTTON DETECT
MIN TYP MAX MIN TYP MAX
DS1233-15 4.0 4.125 4.24 2.4 - 3.3
DS1233-10 4.25 4.375 4.49 2.4 - 3.3
DS1233-5 4.5 4.625 4.75 2.4 - 3.3
DS1233D-15 4.0 4.125 4.24 N/A N/A
DS1233D
5V
3.3V
DS1233D-10 4.25 4.375 4.49 N/A N/A
DS1233D-5 4.5 4.625 4.75 N/A N/A
DS1833-15 4.0 4.125 4.24 N/A N/A
DS1833-10 4.25 4.375 4.49 N/A N/A
DS1833-5 4.5 4.625 4.75 N/A N/A
DS1233A-15 2.64 2.72 2.80 1.8 - 3.0
DS1233A-10 2.8 2.88 2.97 1.8 - 3.0
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